<!-- ============================================================= -->
<!--  MODULE:    Journal Article Metadata Elements                 -->
<!--  VERSION:   2.0                                               -->
<!--  DATE:      August 2004                                       -->
<!--                                                               -->
<!-- ============================================================= -->

<!-- ============================================================= -->
<!--                    PUBLIC DOCUMENT TYPE DEFINITION            -->
<!--                        TYPICAL INVOCATION                     -->
<!--
"-//NLM//DTD Archiving and Interchange DTD Suite Journal Article Metadata Elements v2.0 20040830//EN"
     Delivered as file "articlemeta.ent"                           -->
<!-- ============================================================= -->

<!-- ============================================================= -->
<!-- SYSTEM:     Archiving and Interchange DTD Suite               -->
<!--                                                               -->
<!-- PURPOSE:    Names all elements used to describe the journal   --> 
<!--             in which the journal article is published.        -->
<!--                                                               -->
<!-- CONTAINS:   1. Article element parameter entity               -->
<!--             2. Article metadata elements in alphabetical      -->
<!--                order                                          -->
<!--                                                               -->
<!-- CREATED FOR:                                                  -->
<!--             Digital archives and publishers who wish to       -->
<!--             create a custom XML DTD for original markup of    -->
<!--             journal literature, books, and related material,  -->
<!--             or for archiving and transferring such material   -->
<!--             between archives.                                 -->
<!--                                                               -->
<!--             This DTD is in the public domain. An organization -->
<!--             that wishes to create its own DTD from the suite  -->
<!--             may do so without permission from NLM.            -->
<!--                                                               -->
<!--             The suite has been set up to be extended using a  -->
<!--             new DTD file and a new DTD-specific customization -->
<!--             module to redefine the many Parameter Entities.   -->
<!--             Do not modify the suite directly or redistribute  -->
<!--             modified versions of the suite.                   -->
<!--                                                               -->
<!--             In the interest of maintaining consistency and    -->
<!--             clarity for potential users, NLM requests:        -->
<!--                                                               -->
<!--             1. If you create a DTD from the Archiving and     -->
<!--                Interchange DTD Suite and intend to stay       -->
<!--                compatible with the suite, then please include -->
<!--                the following statement as a comment in all of -->
<!--                your DTD modules:                              -->
<!--                   "Created from, and fully compatible with,   -->
<!--                    the Archiving and Interchange DTD Suite."  -->
<!--                                                               -->
<!--             2. If you alter one or more modules of the suite, -->
<!--                then please rename your version and all its    -->
<!--                modules to avoid any confusion with the        -->
<!--                original suite. Also, please include the       -->
<!--                following statement as a comment in all your   -->
<!--                DTD modules:                                   -->
<!--                   "Based in part on, but not fully compatible -->
<!--                    with, the Archiving and Interchange DTD    --> 
<!--                    Suite."                                    -->
<!--                                                               -->
<!--             Suggestions for refinements and enhancements to   -->
<!--             the DTD suite should be sent in email to:         -->
<!--                 archive-dtd@ncbi.nlm.nih.gov                  -->
<!--                                                               -->
<!-- ORIGINAL CREATION DATE:                                       -->
<!--             December 2002                                     -->
<!--                                                               -->
<!-- CREATED BY: Jeff Beck       (NCBI)                            -->
<!--             Deborah Lapeyre (Mulberry Technologies, Inc.)     -->
<!--             Bruce Rosenblum (Inera Inc.)                      -->
<!--                                                               -->
<!--             NLM thanks the Harvard University Libraries, both -->
<!--             for proposing that a draft archiving NLM DTD for  --> 
<!--             life sciences journals be extended to accommodate -->
<!--             journals in all disciplines and for sponsoring    -->
<!--             Bruce Rosenblum's collaboration with other DTD    -->
<!--             authors in completing Version 1.0. The Andrew W.  --> 
<!--             Mellon Foundation provided support for these      --> 
<!--             important contributions.                          -->
<!--                                                               -->
<!-- ============================================================= -->


<!-- ============================================================= -->
<!--                    DTD VERSION/CHANGE HISTORY                 -->
<!-- ============================================================= -->
<!--

     =============================================================

Version  Reason/Occasion                   (who) vx.x (yyyy-mm-dd)

     =============================================================
     Version 2.0                       (DAL/BTU) v2.0 (2004-08-30)
     
     
     Major requirement changes led to the new release, producing
     DTD version "2.0":
       a) The splitting of the Archival and Interchange Tag Set 
          DTDs into three DTDs from two: an authoring DTD, an
          archive regularization and interchange DTD (the
          current Blue Publishing DTD), and a preservationist 
          archive DTD (the current Green Archiving and Interchange 
          DTD).
       b) AIT Working Group suggestions from the June 04 meeting 
          and June/July 2004 followup discussions
       c) Suite remodularization to meet new (and newly articulated)
          modularization requirements
       d) New or renamed classes and mixes to make modifications
          easier and more consistent

 13. CONTRACT NAME/CONTRACT SPONSOR ATTRIBUTES - Added new attributes
     to both these elements through a new PE %contract-atts;:
      - id  (ID)
      - rid (IDREFS)
      - %might-link-atts;

 12. ROLE ELEMENT
     a. Added to the model for <citation>
     b. Therefore the element declaration for <role> was
        moved from this module into the common module.

 11. DEFAULT ARTICLE-META-MODEL - Added the following 
     elements to -%article-meta-model;:
     Existing elements:
        - <email>
     New elements:
       - <license> (for now, just a bucket into which to
         dump license-related material until the AIT Workgroup
         does more analysis
       - <issue-id> (existing <issue> means issue number)
       - <issue-title> (for special title or theme)
       - <page-range>
       - <volume-id> (existing <volume> means volume number)
       - <custom-meta-wrap> Which is a wrapper element used to hold
         name/value pairs for metadata elements that are in source
         material but were never envisioned by this DTD.

 10. CONTRIBUTOR / CONTRIBUTOR GROUP
     a. Made model into Parameter Entity %contrib-model;
     b. Allowed <string-name> as an alternative to <name>
     c. Allowed <degrees> to follow either <name> or 
        <string-name>
     d. Moved <etal> to %contrib-info.class; to solve \
        classing problems
     e. Added footnote <fn> to %contrib-info.class;

  9. STRING NAME
     a. Created a new element <string-name> for names that
        do not follow the former, strict personal name model.

     b. Allowed <string-name> to be used anywhere <name> is
        used. Inside
         - <product> (by adding to %references.class; used in 
           %product-elements;)
         - <contrib> (by adding to %name.class; used in 
           %contrib-model;)

  8. DOI - added to elements by request of AIT WG. Elements with
     DOIs are those a publisher could expect to sell or handle
     separately. DOI added to: (using <object-id> element)
      - <abstract> (through %abstract-model;)

  7. COMPLETE MODELS WHEN OVER-RIDING A MODEL 
     (for all Parameter Entities suffixed "-model")
     ### Customization Alert ###
     Added internal parenthesis to Parameter Entity and removed 
     them from Element Declaration for:
     - %abstract-model;
     - %article-meta-model;
     - %author-notes-model;
     - %contrib-group-model;
     - %contrib-model;
     - %counts-model;
     - %date-model;
     - %title-group-model;
     - %trans-abstract-model;
 
  6. RENAMED CONTENT MODEL PARAMETER ENTITY
     ### Customization Alert ###
     - %author-notes-elements; ==> -%author-notes-model;

  5. PARAMETER ENTITIES FOR CLASSES/MIXES/ATT LISTS
     a. RENAMED CLASSES
        ### Customization Alert ###
         Not all class names ended in the ".class" suffix. 
         Changed the following to add that suffix:
         - %address-elements; (renamed -%address.class;!)
               used in -%corresp-elements; 
         - %contrib-info.class; used in -%contrib-group-model; 
               and in -%contrib-model;
         - %inline-math.class; used in -%subject-elements;
               and in -%kwd-elements; (via %all-phrase;)

     b. DEFAULT CLASSES - Were moved from this module to 
        the module -%default-classes.ent;

     c. NEW PARAMETER ENTITIES - To correct potential classing 
        problems,  new Parameter Entities were created. The following
        PEs and models were changed to use these new PEs:
             New Content model PEs:
        - %date.class;        in %history-elements; 
        - %kwd.class;         in %kwd-group-model;
        - %just-para.class;   in <author-comment>
        
        - %author-comments;   in <author-comments>
        - %contrib-model;     in <contrib>
        - %history-model;     in <history>      
        - %kwd-group-model;   in <kwd-group>
        
        - In <author-notes> "(corresp | fn)+" was replaced
          with the %fn-link.class; and the new class
          -%corresp.class;)

              New Attribute List PEs:
        - %article-id-atts;  for <article-id>

              New mix PEs
        - %degrees-elements;      in <degrees>        
        - %on-behalf-of-elements; in <on-behalf-of>
        - %self-uri-elements; in <self-uri>  
        - %series-text-elements;  in <series-text>  
        - %series-title-elements; in <series-title>

     d. LINK CLASSES -  Replaced %link.class; in the PE
        -%product-elements; with the following classes 
        (no DTD change, just parameterization):
         - %simple-link.class;  (the internal links, same)
         - %article-link.class; (links for journal article)
  
  4. Updated public identifier to "v2.0 20040830"

     =============================================================
     Version 1.1                           (TRG) v1.1 (2003-11-01)
      
  3. Added element <label> to content model of element <author-notes>
     (via %author-notes-elements;) 
     Rationale: To allow label as a format override
  
  2. Created parameter entity %author-notes-elements; to hold 
     contents of <author-notes>
     Rationale: In order to distinguish between models used by
     the Archiving DTD and the Publishing DTD, it was necessary 
     to create a parameter entity that could be overridden.
     
  1. Added parameter entity %label.class; to parameter 
     %corresp-elements;  
     Rationale: To allow label as a format override
                                                                   -->


<!-- ============================================================= -->
<!--                    PARAMETER ENTITY DEPENDENCIES             
                        Requires the following parameter entities
                        be defined before calling this module, 
                        usually accomplished in the Customization
                        Module for the specific DTD:
                                 Classes and Mixes
                        - %address.class; 
                        - %break.class; 
                        - %conference.class;
                        - %contrib-info.class;
                        - %emphasis.class; 
                        - %inline-display.class;
                        - %inline-math.class;
                        - %just-rendition;
                        - %references.class;
                        - %rendition-plus;
                        - %simple-link.class;
                        - %simple-phrase;
                        - %simple-text;
                        - %subsup.class;
                        - %title-elements;
                                Complete Content Models
                        - %article-meta-model;
                        - %date-model; 
                        - %sec-opt-title-model; 
                                 Attribute Values
                        - %pub-id-types;         
                                 Attribute Lists
                        - %might-link-atts; 
                                                                   -->
<!-- ============================================================= -->


<!-- ============================================================= -->
<!--                    PARAMETER ENTITIES FOR ATTRIBUTE VALUES    -->
<!-- ============================================================= -->


<!--                    PUBLICATION TYPES                          -->
<!--                    Used to record the type of publication, for
                        example a print-only publication versus
                        an electronic-only publication, in any of
                        several life stages.
                          This Parameter Entity is intended to name
                        the values of the "pub-type" attribute, but
                        in Version 1.0 of this DTD Suite, the 
                        "pub-type" attribute is defined with a
                        Declared Value of CDATA and this Parameter
                        Entity is not used or provide its values.
                        Suggested values include:
                          epub        - Electronic publication
                          ppub        - Print publication
                          epub-ppub   - Published in both print and
                                        electronic form
                          epreprint   - Electronic preprint 
                                        dissemination    
                          ppreprint   - Print preprint dissemination
                          ecorrected  - Corrected in electronic    
                          pcorrected  - Corrected in print     
                          eretracted  - Retracted in electronic    
                          pretracted  - Retracted in print         -->
<!ENTITY % pub-types    "epub | ppub | epub-ppub | epreprint |
                         ppreprint | ecorrected | pcorrected | 
                         eretracted | pretracted"                    >


<!-- ============================================================= -->
<!--                    PARAMETER ENTITIES FOR ATTRIBUTE LISTS     -->
<!-- ============================================================= -->
                                                                
                                                                 
<!--                    ABSTRACT ATTRIBUTES                        -->
<!--                    Attributes for the <abstract> element and
                        the <trans-abstract> element               -->
<!ENTITY % abstract-atts
            "abstract-type   
                        CDATA                              #IMPLIED
             xml:lang   NMTOKEN                            #IMPLIED" > 
                                                                
                                                                 
<!--                    ALTERNATE TITLE ATTRIBUTES                 -->
<!--                    Attributes for the <alt-title> element     -->
<!--         alt-title-type
                        Why this title was created, for example,
                        "short" for a short version of the title,
                        "toc" for use in a Table of Contents, "ASCII" 
                        for an ASCII title, "right-running" for
                        a right-running-head title, etc.           -->
<!ENTITY % alt-title-atts
            "alt-title-type
                        CDATA                              #IMPLIED" >
                                                                
                                                                 
<!--                    ARTICLE IDENTIFIER ATTRIBUTES              -->
<!--                    Attributes for the <article-id> element
             pub-id-type
                        Publication (article) Identifier Type
                        Names the type of identifier, or the 
                        organization or system that defined this 
                        identifier for the identifier of the journal 
                        article or a cited publication.
                           Used on the <article-id> element, which 
                        holds an identifier for the entire article.  
                           Also used on the <pubid> element, which 
                        is an identifier for a publication cited in 
                        a bibliographic reference (citation).
                        Valid Types include:
                          coden  - Obsolete PDB/CCDC identifier (may
                                   be present on older articles)
                          doi    - Digital Object Identifier
                          medline- NLM Medline identifier
                          other  - None of the named identifiers
                          pii    - Publisher Item Identifier, see
                                    http://pubs.acs.org/epub/piius.htm
                                   or 
                                    http://www.aip.org/epub/piipr.html
                          pmid   - PubMed ID (see
                                   www.ncbi.nlm.nih.gov/entrez/
                                   query.fcgi?db=PubMed)         
                          publisher-id 
                                 - Publisher's identifier such 
                                   as an 'article-id', 'artnum',
                                   'identifier', 'article- number', 
                                   'pub-id', etc.
                          sici   - Serial Item and Contribution 
                                   Identifier (SICI). A journal 
                                   article may have more than one 
                                   SICI, one for a print version and
                                   one for an electronic version.  -->
<!ENTITY % article-id-atts
            "pub-id-type
                        (%pub-id-types;)                   #IMPLIED" >
                                                                
                                                                 
<!--                    CONTRACT ATTRIBUTES                        -->
<!--                    Attributes for the <contract-num> element and
                        the <contract-sponsor> element            
             id         Unique identifier, so the contributor can be
                        referenced
             rid        May be used to point to, for example, link
                        contract numbers and sponsors
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename associated with
                        a grant or sponsor                         -->
<!ENTITY % contract-atts
            "id         ID                                 #IMPLIED
             rid        IDREFS                             #IMPLIED
             %might-link-atts;"                                      >

                                                                 
<!--                    CONTRIBUTOR ATTRIBUTES                     -->
<!--                    Attributes for the Contributor <contrib> 
                        element                                    -->
<!--         contrib-type
                        What was the contribution of this person,
                        for example: author, editor, contributor,
                        translator, illustrator, designer, 
                        research assistant, etc.                 
             id         Unique identifier, so the contributor can be
                        referenced
             corresp    Corresponding Author (Set to 'yes' if this 
                        contributor is a corresponding author.)
             equal-contrib    
                        Contributed equally (Set to 'yes' if all 
                        contributors contributed equally.)
             deceased   Deceased (Set to 'yes' if the contributor
                        has died.)                           
             rid        May be used to point to information concerning
                        the contributor, for example to the <corresp>
                        Corresponding Information element.  There
                        is no limit to the number of contributors 
                        that can be designated as corresponding.
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename.               -->
<!ENTITY % contrib-atts
            "contrib-type       
                        CDATA                              #IMPLIED  
             id         ID                                 #IMPLIED
             corresp    (no | yes)                         #IMPLIED        
             equal-contrib 
                        (no | yes)                         #IMPLIED  
             deceased   (no | yes)                         #IMPLIED 
             rid        IDREFS                             #IMPLIED  
             %might-link-atts;                                     " >
             
             
<!--                    CUSTOM METADATA ATTRIBUTES                 -->
<!--                    Attributes for the <custom-meta> element   -->
<!ENTITY % custom-meta-atts
            "used-by    CDATA                              #IMPLIED
             %might-link-atts;"                                      >
                                                                
                                                                 
<!--                    KEYWORD GROUP ATTRIBUTES                   -->
<!--                    Attributes for the <kwd-group> element     -->
<!ENTITY % kwd-group-atts
            "id         ID                                 #IMPLIED 
             kwd-group-type  
                        CDATA                              #IMPLIED
             xml:lang   NMTOKEN                            #IMPLIED" >
                                                                
                                                                 
<!--                    LICENSE ATTRIBUTES                         -->
<!--                    Attributes for the <license> element    
             license-type
                        xxx ask Jeff xxx
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename.               -->
<!ENTITY % license-atts
            "license-type  
                        CDATA                              #IMPLIED
             %might-link-atts;"                                      >
                                                                
                                                                 
<!--                    PRODUCT ATTRIBUTES                         -->
<!--                    Attributes for the Product <product> 
                        element                                    -->
<!--         product-type
                        Type of product being reviewed, for example:
                        book, software package, journal or journal
                        issue, website, film, hardware component,
                        etc.
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename                -->
<!ENTITY % product-atts
            "product-type 
                        CDATA                              #IMPLIED           
             %might-link-atts;"                                      >

                                                                 
<!--                    PUBLICATION DATE ATTRIBUTES                -->
<!--                    Attributes for the <pub-date> element      -->
<!--                    Used to record the type of publication, for
                        example a print-only publication versus
                        an electronic-only publication, in any of
                        several life stages.
                        Suggested values include: 
                          epub        - Electronic publication
                          ppub        - Print publication
                          epub-ppub   - Published in both print and
                                        electronic form
                          epreprint   - Electronic preprint 
                                        dissemination    
                          ppreprint   - Print preprint dissemination     
                          ecorrected  - Corrected in electronic    
                          pcorrected  - Corrected in print     
                          eretracted  - Retracted in electronic    
                          pretracted  - Retracted in print     
                                                                   -->
<!ENTITY % pub-date-atts
            "pub-type   CDATA                              #IMPLIED" >


<!--                    SUBJECT GROUP ATTRIBUTES                   -->
<!--                    Attributes for the <subj-group> element    -->
<!--         xml:lang   The language in which the value of the
                        element is expressed.  Recommended best 
                        practice is to use values as defined in
                        RFC 1766, typically 2-letter language
                        codes such as "FR" (French), "EN" (English),
                        and "DE" (German). These values are NOT
                        case sensitive, so "EN" = "en". The values
                        may include hyphenated differentiations such 
                        as "EN-AU" (Australian English) and "EN-US"
                        (United States English).                   
             subj-group-type
                        Identification of the subject, information
                        class, or type of this particular subject
                        group                                      -->
<!ENTITY % subj-group-atts
            "xml:lang   NMTOKEN                            #IMPLIED 
             subj-group-type
                        CDATA                              #IMPLIED" > 


<!--                    SUPPLEMENT ATTRIBUTES                      -->
<!--                    Attributes for the <supplement> element    -->
<!--        supplement-type   
                        Indicates what sort of supplement, if the
                        for example: "issue" meaning a supplement to 
                        a particular journal issue; "conference", 
                        meaning the supplement contains information 
                        from a conference, symposium, or other 
                        gathering; "periodic" for supplements issued  
                        at regular intervals, etc.                 -->
<!ENTITY % supplement-atts
            "supplement-type   
                        CDATA                              #IMPLIED" >


<!-- ============================================================= -->
<!--                    ARTICLE METADATA                           -->
<!-- ============================================================= -->


<!--                    ARTICLE METADATA MODEL                     -->
<!--                    Complete content model for the <article-meta>
                        element, which names the journal article
                        metadata                                   -->
<!ENTITY % article-meta-model  
                        "(article-id*, article-categories?, 
                         title-group?, (contrib-group | aff)*, 
                         author-notes?, pub-date*, 
                         volume?, volume-id*, 
                         issue?, issue-id*, issue-title*,  
                         supplement?, 
                         ( (fpage, lpage?, page-range?) | 
                            elocation-id )?, 
                         (%address-link.class; | product |
                          supplementary-material)*, 
                         history?, copyright-statement?, 
                         copyright-year?, license?, 
                         self-uri*, related-article*, abstract*, 
                         trans-abstract*, kwd-group*,
                         contract-num*, contract-sponsor*,
                         conference*, counts?, custom-meta-wrap?)"   >


<!--                    ARTICLE METADATA                           -->
<!--                    Metadata that identifies this article, for
                        example, bibliographic information such as
                        the title, author, and copyright year.     -->
<!ELEMENT  article-meta %article-meta-model;                         >


<!--ELEM   copyright-statement
                        Defined in %common.ent"                    -->


<!-- ============================================================= -->
<!--                    ARTICLE METADATA ELEMENTS                  -->
<!-- ============================================================= -->


<!-- ============================================================= -->
<!--                    ARTICLE IDENTIFICATION                     -->
<!-- ============================================================= -->


<!--                    ARTICLE IDENTIFIER                         -->
<!--                    Optional element, used to hold one of the
                        "unique identifiers" that have been assigned
                        at various times to an article.  Such
                        identifiers may come from the publisher, the
                        jobber, or from inside PMC. Examples of such
                        numbers are the publishers tracking number,
                        the PNAS number, etc. PMC tries to carry 
                        all identifiers associated with an article,
                        whether they came in as elements or attributes
                        on the original article.
                          The "type attribute" should only be used if
                        the type is known, for example, to identify
                        DOIs.
                          REMARKS: The <article-id> element is one
                        of three elements used to provide an element
                        identifier (such as a DOI). The <article-id>
                        holds an identifier for Articles. The 
                        <pub-id> element holds an identifier for  
                        cited publications, such as a journal article
                        listed inside the bibliographic reference 
                        list <ref-list>. The <object-id> holds an
                        identifier for an object such as a Figure or
                        sidebar <boxed-text>. All three elements
                        take the "pub-id-type" attribute.          -->
<!ELEMENT  article-id   (#PCDATA)                                    >
<!--         pub-id-type
                        Publication (article) Identifier Type
                        Names the type of identifier, or the 
                        organization or system that defined this 
                        identifier for the identifier of the journal 
                        article or a cited publication.
                           Used on the <article-id> element (article
                        metadata), the <pub-id> element (cited
                        publications in the reference list), and
                        in the <object-id> element (used on Figures,
                        etc. to provide a DOI or other ID).
                          For the Archiving (Green) DTD, this is a
                        CDATA attribute with the following types
                        suggested. Other DTDs may enforce the
                        types. Valid/suggested types include:
                          coden  - Obsolete PDB/CCDC identifier (may
                                   be present on older articles)
                          doi    - Digital Object Identifier
                          medline- NLM Medline identifier
                          other  - None of the named identifiers
                          pii    - Publisher Item Identifier, see
                                    http://pubs.acs.org/epub/piius.htm
                                   or 
                                    http://www.aip.org/epub/piipr.html
                          pmid   - PubMed ID (see
                                   www.ncbi.nlm.nih.gov/entrez/
                                   query.fcgi?db=PubMed)         
                          publisher-id 
                                 - Publisher's identifier such 
                                   as an 'article-id', 'artnum',
                                   'identifier', 'article- number', 
                                   'pub-id', etc.
                          sici   - Serial Item and Contribution 
                                   Identifier (SICI). A journal 
                                   article may have more than one 
                                   SICI, one for a print version and
                                   one for an electronic version.  -->
<!ATTLIST  article-id  
             %article-id-atts;                                       >
             

<!-- ============================================================= -->
<!--                    ARTICLE GROUPING DATA (ARTICLE METADATA)   -->
<!-- ============================================================= -->


<!--                    ARTICLE GROUPING DATA                      -->
<!--                    Container for elements that may be used to
                        group articles into related clusters       -->
<!ELEMENT  article-categories    
                        (subj-group*, series-title*, series-text?)   >
                                                                  

<!--                    GROUPING ARTICLES IN TITLED CATEGORIES
                        For some journals, articles are grouped into
                        categories, with the category indicated in
                        the article's display.
                        Sometimes the grouping or category refers
                        to the type of article, such as "Essay",
                        "Commentary", or "Article".  Sometimes the
                        grouping refers to subject areas, such as
                        "Physical Sciences", "Biological Sciences",
                        or "Social Sciences". Sometimes the grouping 
                        refers to topics within the larger subject 
                        areas, such as "Applied Math", "Biology", or 
                        "Chemistry".

                        In a printed journal as well as on the PMC
                        website, articles may be grouped or arranged
                        under these headings (here are all the
                        Essays, here are all the Biology articles,
                        etc.) Some journals divide articles into 
                        three layers of grouping, some into two, and 
                        some into only one.
                        For example, a three level grouping might be:
                         <subj-group>
                           <subject>Articles</subject>
                           <subj-group>
                             <subject>Biological Sciences</subject>
                             <subj-group>
                               <subject>Entomology</subject>
                             </subj-group>
                           </subj-group>
                         </subj-group>
                        And a one-level grouping might be
                         <subj-group>
                          <subject>Retraction</subject>
                         </subj-group>
                        or, alternatively
                         <subj-group>
                          <subject>Essay</subject>
                         </subj-group>
                         
                        Articles may also be assigned to more than 
                        one grouping. For example, if an article is
                        classified as "Biochemistry" under 
                        "Biological Sciences" and "Chemistry" under
                        "Physical Sciences," the subj-group wrapper
                        may repeat. 
                         
                        For example, 
                         <subj-group>
                           <subject>Articles</subject>
                           <subj-group>
                             <subject>Biological Sciences</subject>
                             <subj-group>
                               <subject>Biochemistry</subject>
                             </subj-group>
                           </subj-group>
                           <subj-group>
                             <subject>Physical Sciences</subject>
                             <subj-group>
                                <subject>Chemistry</subject>
                             </subj-group>
                         </subj-group>
                                                                   -->
<!ELEMENT  subj-group   (subject+, subj-group*)                      > 
<!--         xml:lang   The language in which the value of the
                        element is expressed.  Recommended best 
                        practice is to use values as defined in
                        RFC 1766, typically 2-letter language
                        codes such as "FR" (French), "EN" (English),
                        and "DE" (German). These values are NOT
                        case sensitive, so "EN" = "en". The values
                        may include hyphenated differentiations such 
                        as "EN-AU" (Australian English) and "EN-US"
                        (United States English).                   
             subj-group-type
                        Identification of the subject, information
                        class, or type of this particular subject
                        group                                      -->
<!ATTLIST  subj-group
             %subj-group-atts;                                       > 


<!--                    SUBJECT GROUPING NAME ELEMENTS             -->
<!--                    Elements that may be used, along with data
                        characters inside the content model of the
                        <subject> element                          -->
<!ENTITY % subject-elements
                        "| %emphasis.class; | %inline-display.class; | 
                         %inline-math.class; | %subsup.class;"       > 


<!--                    SUBJECT GROUPING NAME                      -->
<!--                    The name of one of the subject groups used
                        to describe an article.  Such groups are
                        used, typically, to provide headings for
                        groups of articles in a printed or online
                        generated Table of Contents.               -->
<!ELEMENT  subject      (#PCDATA %subject-elements;)*                >


<!-- ============================================================= -->
<!--                    SERIES INFORMATION                         -->
<!-- ============================================================= -->
                        

<!--                    GROUPING ARTICLES IN SERIES
                        Series (as used in the <series-title> and 
                        <series-text> elements described below) is 
                        used in two different senses. Some issues of
                        journals are part of a series and will have
                        series information just as they have an
                        issue number as part of the article metadata,
                        to describe the issue of the journal in which
                        the article is published.  The second usage
                        is for groupings of articles within one
                        issue of a journal. For example, in some 
                        journals, articles are grouped into a
                        series such as "From the Cover" and 
                        identified as part of a series. 
                        The Series Title element names the series 
                        and the Series Text element provides textual
                        description (if any) describing the series.-->


<!--                    SERIES TITLE ELEMENTS                      -->
<!--                    Elements that may be used, along with data
                        characters inside the content model of the
                        <series-title> element                     -->
<!ENTITY % series-title-elements
                        "%rendition-plus;"                           >


<!--                    SERIES TITLE                               -->
<!--                    Title of the journal series (bibliographic
                        meaning) or the title of a  series of 
                        articles internal to one issue of a journal
                                                                   -->
<!ELEMENT  series-title (#PCDATA %series-title-elements;)*           >


<!--                    SERIES TEXT ELEMENTS                       -->
<!--                    Elements that may be used, along with data
                        characters inside the content model of the
                        <series-text> element                      -->
<!ENTITY % series-text-elements
                        "%rendition-plus;"                           >
    

<!--                    SERIES TEXT: HEADER TEXT to DESCRIBE       -->
<!--                    Textual description of the series of articles
                        that are named in a <series-title> element -->
<!ELEMENT  series-text  (#PCDATA %series-text-elements;)*            >


<!-- ============================================================= -->
<!--                    TOP-LEVEL ARTICLE METADATA CONTINUED       -->
<!-- ============================================================= -->


<!--                    AUTHOR NOTE MODEL                          -->
<!--                    Content model for an <author-notes> element.
                                                                   -->
<!ENTITY % author-notes-model 
                        "((%label.class;)*, title?, 
                          (%corresp.class; | %fn-link.class;)+ )"    >


<!--                    AUTHOR NOTE GROUP                          -->
<!--                    Footnotes to authors or notes about authors
                        (and, potentially other contributors) are
                        collected in the Author note group.  
                        References to these footnotes are made 
                        using the <xref> element.
                        Authoring Note:  While this element 
                        contains an optional Label element, the 
                        Label element should be included only in 
                        those circumstances where a formatting 
                        override is needed; Label should NOT 
                        be used in the ordinary course of 
                        tagging.                                   -->
<!ELEMENT  author-notes %author-notes-model;                         >
<!--         id         Unique identifier so that the note group
                        may be referenced, for example by an author
             rid        May be used to point to an author, if the
                        source has recorded connections in both
                        directions                                 -->
<!ATTLIST  author-notes
             id         ID                                 #IMPLIED  
             rid        IDREFS                             #IMPLIED  >


<!--ELEM   volume       Defined in %common.ent;                    -->
<!--ELEM   issue        Defined in %common.ent;                    -->
<!--ELEM   supplement   Defined in %common.ent;                    -->
<!--ELEM   fpage        Defined in %common.ent;                    -->
<!--ELEM   lpage        Defined in %common.ent;                    -->
<!--ELEM   elocation-id Defined in %common.ent;                    -->
<!--ELEM   ext-link     Defined in %common.ent;                    -->
<!--ELEM   lpage        Defined in %common.ent;                    -->


<!-- ============================================================= -->
<!--                 PRODUCT REVIEW INFORMATION (PRODUCT METADATA) -->
<!-- ============================================================= -->


<!--                    PRODUCT ELEMENTS                           -->
<!--                    Elements that may be used inside the 
                        <product> element                          
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an inline
                        mix, the OR bar is already there.          -->
<!ENTITY % product-elements   
                        "%simple-text; | %article-link.class; |  
                         %break.class; |  %references.class; | 
                         %simple-link.class;"                        > 


<!--                    PRODUCT INFORMATION                        --> 
<!--                    Used as a wrapper for metadata for a product
                        (such as a book, software package, hardware
                        component, website etc.) that is being 
                        reviewed. 
                        Authoring and Conversion Note: This element 
                        should be used when the value of the 
                        "article-type" attribute on the element 
                        <article> is "book-review" or 
                        "product-review".
                        
                        Authoring and Conversion Note: A review of 
                        a book, journal, website, etc. should 
                        include as much information about the item
                        being reviewed as is practical, for example:
                        <product>
                            <name>
                              <surname>Lapeyre</surname>
                              <given-names>Deborah A.</given-names>
                            </name>
                            <name>
                              <surname>Usdin</surname>
                              <given-names>B. Tommie</given-names>
                            </name>
                            <source>Wildflowers of the
                            Washington Area</source>
                            <year>2002</year>
                            <publisher-name>Lippman Ltd.
                            </publisher-name>
                            <publisher-loc>Bethesda, MD
                            </publisher-loc>
                            <isbn>0-23-8675-309</isbn>, 
                            includes a CD-ROM, 
                            <bold>$19.95</bold> (Used 12.50 when
                            available)
                         </product>
                                                                   -->
<!ELEMENT  product      (#PCDATA %product-elements;)*                >
<!--         product-type
                        Type of product being reviewed, for example:
                        book, software package, journal or journal
                        issue, website, film, hardware component,
                        etc.
              xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename                -->
<!ATTLIST  product
             %product-atts;                                          >


<!-- ============================================================= -->
<!--                    PUBLICATION HISTORY ELEMENTS               -->
<!-- ============================================================= -->


<!--                    HISTORY MODEL                              -->
<!--                    The content model for the <history> element
                                                                   -->
<!ENTITY % history-model   
                        "(%date.class;)+"                            > 


<!--                    HISTORY:  DOCUMENT HISTORY                 -->
<!--                    Used as a container for dates related to the 
                        processing history of the document, such as 
                        received date and accepted date.           
                        Authoring and Conversion Note: The dates 
                        inside the <history> element are used to
                        preserve events other than publication dates
                        in the lifecycle of the article. Publication
                        dates are considered to be an important
                        part of the metadata. History dates include
                        accepted date, received date, reviewed
                        date, and other dates that may be important
                        to the publisher but are not a likely part 
                        of the article metadata for searching, 
                        building a DOI, etc.                       -->
<!ELEMENT  history      %history-model;                              >


<!-- ============================================================= -->
<!--                    FURTHER METADATA ELEMENTS                  -->
<!-- ============================================================= -->


<!--                    COPYRIGHT YEAR                             -->
<!--                    Year of the copyright. Need not be used, if,
                        for example, having the year as part of the 
                        copyright statement is sufficient.
                        Note: since Copyright Statement is intended
                        for display, Copyright Year is not expected 
                        to be displayed (but will be available for 
                        searching).                                -->
<!ELEMENT  copyright-year    
                        (#PCDATA)                                    >


<!--                    LICENSE MODEL                              -->
<!--                    Content model for an <license> element     -->
<!ENTITY % license-model
                        "((%just-para.class;)+)"                     > 


<!--                    LICENSE INFORMATION                        -->
<!--                    The set of conditions under which people are
                        allowed to use this article or other
                        license-related information or restrictions.
                        For now, this is a place-holder element
                        that may change after the AIT Workgroup has
                        done additional analysis                   -->
<!ELEMENT  license      %license-model;                              >
<!ATTLIST  license  
             %license-atts;                                          >


<!--                    SELF-URI ELEMENTS                          -->
<!--                    Elements to be mixed with data characters
                        inside the <self-uri> element              -->
<!ENTITY % self-uri-elements
                        " "                                          >
 

<!--                    URI FOR THIS SAME ARTICLE ONLINE           -->
<!--                    Sometimes an article is available in several
                        forms, for example there is the version that
                        was published in print and there is the same
                        article (possibly expanded or with different
                        graphics) available online.              
                           The URI (such as a URL) may be used as a 
                        live link, typically naming a website or the 
                        element content may name the URL, e.g., and
                        use the link attributes to hold the real link:
                           <self-uri xlink:href="...">An expanded
                           version of this article is available
                           online</self-uri>                       -->
<!ELEMENT  self-uri     (#PCDATA %self-uri-elements;)*               >
<!ATTLIST  self-uri 
             %might-link-atts;                                       >


<!--ELEM   related-article       
                        Defined in %common.ent;                    -->


<!-- ============================================================= -->
<!--                    ABSTRACTS                                  -->
<!-- ============================================================= -->


<!--                    ABSTRACT MODEL                             -->
<!--                    Content model for an <abstract> element    -->
<!ENTITY % abstract-model
                        "((%id.class;)*, %sec-opt-title-model; )"    > 


<!--                    ABSTRACT                                   -->
<!ELEMENT  abstract     %abstract-model;                             >
<!--         abstract-type   
                        What type of abstract, for the various
                        styles of abstracts that publishers
                        identify, such as:
                          ASCII        Without special characters or
                                       equations so it can be sent in
                                       email or displayed on primitive
                                       browsers
                           executive-summary 
                                       A non-technical summation of
                                       the major findings of the
                                       article
                           graphical   The abstract is a picture
                           editor      For an abstract written by an
                                       editor and not the author
                           key-points  An abstract which is a list of
                                       the key points made by the 
                                       document
                           objectives  Used for Learning Objectives 
                                       or article objectives
                           short       An abbreviated form of the
                                       abstract, for use, for example
                                       inside a generated Table of
                                       Contents, or to be returned
                                       in addition to the article 
                                       title during a search
                           stereochemical 
                                       An abstract containing only
                                       the details of a chemical
                                       compound (For example, the
                                       Elsevier DTD "stereochem")
                           summary     Summation of the article,
                                       typically used in conjunction
                                       with other types of abstracts
                           teaser      A short abstract specifically
                                       written to draw the attention
                                       of the reader
                           toc         A line or two that displays
                                       in a table of contents
                           web-summary
                                       Short summary intended for
                                       distribution on a website   -->
<!ATTLIST  abstract
             %abstract-atts;                                         >


<!--                    TRANSLATED ABSTRACT MODEL                  -->
<!--                    Content model for an <trans-abstract> element.
                        The section model include the parentheses. -->
<!ENTITY % trans-abstract-model
                        "%sec-opt-title-model;"                      > 


<!--                    TRANSLATED ABSTRACT                        -->
<!--                    An abstract that has been translated into
                        another language                           -->
<!ELEMENT  trans-abstract
                        %trans-abstract-model;                       >
<!--         abstract-type
                        What type of abstract, for the various
                        unusual styles of abstracts that publishers
                        identify, such as "short" abstract, "graphic"
                        abstract, "ASCII" abstract, "stereochemical"
                        abstract, etc.                            
             xml:lang   The language in which the value of the
                        element is expressed.  Recommended best 
                        practice is to use values as defined in
                        RFC 1766, typically 2-letter language
                        codes such as "FR" (French), "EN" (English),
                        and "DE" (German). These values are NOT
                        case sensitive, so "EN" = "en". The values
                        may include hyphenated differentiations such 
                        as "EN-AU" (Australian English) and "EN-US"
                        (United States English).                   -->
<!ATTLIST  trans-abstract
             %abstract-atts;                                         > 


<!-- ============================================================= -->
<!--                    KEYWORD ELEMENTS                           -->
<!-- ============================================================= -->


<!--                    KEYWORD GROUP MODEL                        -->
<!--                    Content model for a <kwd-group> element    -->
<!ENTITY % kwd-group-model
                        "(title?, (%kwd.class;)+ )"                  > 


<!--                    KEYWORD GROUP                              -->
<!--                    Container element for one set of keywords 
                        used to describe a document.
                        Remarks: A document may have multiple sets
                        of keywords, each with a source named in
                        the "kwd-group-type" attribute.            -->
<!ELEMENT  kwd-group    %kwd-group-model;                            >
<!--         id         Unique identifier so the element may be
                        referenced                                
             kwd-group-type  
                        Name of the source of the keywords, for
                        example "MESH", "IEEE", "author",
                        "ICD9-codes", etc.
             xml:lang   The language in which the value of the
                        element is expressed.  Recommended best 
                        practice is to use values as defined in
                        RFC 1766, typically 2-letter language
                        codes such as "FR" (French), "EN" (English),
                        and "DE" (German).  These values are NOT
                        case sensitive, so "EN" = "en". The values
                        may include hyphenated differentiations such 
                        as "EN-AU" (Australian English) and "EN-US"
                        (United States English).                   -->
<!ATTLIST  kwd-group
             %kwd-group-atts;                                        >


<!--ELEM   title        Defined in %common.ent;                    -->


<!--                    KEYWORD CONTENT ELEMENTS                   -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        a keyword.                                 -->
<!ENTITY % kwd-elements
                        "| %emphasis.class; | %inline-display.class; | 
                         %inline-math.class; | %simple-link.class; |
                         %subsup.class;"                             >


<!--                    KEYWORD                                    -->
<!--                    One subject term, critical expression, key
                        phrase, abbreviation, indexing word, etc. 
                        that is associated with the whole document
                        and can be used for identification and 
                        indexing purposes.
                        There maybe several sets of keywords,
                        identified by language or vocabulary source
                        at the Keyword Group level <kwd-group>.
                        Conversion Note: Keywords are not allowed to
                        nest.  There are a few journal DTDs in which
                        keyword nesting is used to simulate a two-
                        part list.  These keyword list should be
                        tagged as definition lists instead.        -->
<!ELEMENT  kwd          (#PCDATA %kwd-elements;)*                    >
<!--         id         Unique identifier so the element may be
                        referenced                                 -->
<!ATTLIST  kwd
             id         ID                                 #IMPLIED  >


<!-- ============================================================= -->
<!--                    STILL FURTHER ARTICLE METADATA             -->
<!-- ============================================================= -->


<!--                    CORRESPONDENCE INFORMATION ELEMENTS        -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the correspondence information.            -->
<!ENTITY % corresp-elements 
                        "| %address.class; | %address-link.class;| 
                         %emphasis.class; | %label.class; | 
                         %subsup.class;"                             >


<!--                    CORRESPONDENCE INFORMATION                 -->
<!--                    Optional element, used as a container for 
                        information concerning which of the authors 
                        (or other contributors) is the corresponding 
                        contributor, to whom information requests 
                        should be addressed.
                        A cross-reference element may point to the
                        identifier attribute.
                        Authoring Note:  While this element 
                        contains an optional Label element, the 
                        Label element should be included only in 
                        those circumstances where a formatting 
                        override is needed; Label should NOT 
                        be used in the ordinary course of 
                        tagging.                                   -->
<!ELEMENT  corresp      (#PCDATA %corresp-elements;)*                >
<!--         id         Unique identifier, so the element can be
                        referenced                                 -->
<!ATTLIST  corresp
             id         ID                                 #IMPLIED  >


<!--                    PUBLICATION DATE                           -->
<!--                    Date of publication or release of the
                        material in one particular format.  Inside
                        the article metadata, the Publication Date
                        is allowed to repeat, and each date can take 
                        a "pub-type" attribute to distinguish
                        which form of release or publication.      -->
<!ELEMENT  pub-date     %date-model;                                 >
<!--                    Used to record the type of publication, that
                        was released or published on this date, for
                        example a print-only publication versus
                        an electronic-only publication, in any of
                        several life stages.
                        Suggested values include:
                          epub        - Electronic publication
                          ppub        - Print publication
                          epub-ppub   - Published in both print and
                                        electronic form
                          epreprint   - Electronic preprint 
                                        dissemination    
                          ppreprint   - Print preprint dissemination     
                          ecorrected  - Corrected in electronic    
                          pcorrected  - Corrected in print     
                          eretracted  - Retracted in electronic    
                          pretracted  - Retracted in print         -->
<!ATTLIST  pub-date
             %pub-date-atts;                                         >


<!-- ============================================================= -->
<!--                    CONTRACT/GRANT INFORMATION ELEMENTS        -->
<!-- ============================================================= -->


<!--                    CONTRACT/GRANT NUMBER ELEMENTS             -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the contract number.  
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an inline
                        mix, the OR bar is already there.          -->
<!ENTITY % contract-elements 
                        "%simple-text;"                              >


<!--                    CONTRACT/GRANT NUMBER                      -->
<!--                    Contract or grant number of the supported
                        work described in the article.
                        Authoring Conversion Note: If an acronym of
                        the sponsor is available, it should be
                        inserted before the number.                -->
<!ELEMENT  contract-num
                        (#PCDATA %contract-elements;)*               >
<!--         id         Unique identifier, so the contributor can be
                        referenced
             rid        May be used to point to, for example, link
                        contract numbers and sponsors
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename associated with
                        a grant or sponsor                         -->
<!ATTLIST  contract-num
             %contract-atts;                                         >


<!--                    CONTRACT/GRANT SPONSOR ELEMENTS            -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the contract sponsor.         
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an online
                        mix, the OR bar is already there.          -->
<!ENTITY % contract-sponsor-elements 
                        "%simple-text;"                              >
  

<!--                    CONTRACT/GRANT SPONSOR                     -->
<!--                    Name of the organization that sponsored the
                        work described in the article.
                        proceedings.                               -->
<!ELEMENT  contract-sponsor
                        (#PCDATA %contract-sponsor-elements;)*       >
<!--         id         Unique identifier, so the contributor can be
                        referenced
             rid        May be used to point to, for example, link
                        contract numbers and sponsors
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename associated with
                        a grant or sponsor                         -->
<!ATTLIST  contract-sponsor
             %contract-atts;                                         >


<!-- ============================================================= -->
<!--                    CONFERENCE INFORMATION ELEMENTS            -->
<!-- ============================================================= -->


<!--                    CONFERENCE MODEL                           -->
<!--                    Content model for the <conference> element -->
<!ENTITY % conference-model 
                        "(%conference.class;)*"                      > 


<!--                    CONFERENCE INFORMATION                     -->
<!--                    The container element for the information 
                        about a single conference and its 
                        proceedings.
                        DESIGN NOTE: Conference elements were largely
                        based on Cross-Ref.                        -->
<!ELEMENT  conference   %conference-model;                           >


<!--ELEM   conf-date     Defined in %common.ent;                   -->
<!--ELEM   conf-name     Defined in %common.ent;                   -->


<!--                    CONFERENCE ACRONYM ELEMENTS                -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the conference acronym.   
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an online
                        mix, the OR bar is already there.          -->
<!ENTITY % conf-acronym-elements 
                        "%simple-text;"                              >
 

<!--                    CONFERENCE ACRONYM                         -->
<!--                    The short name, popular name, or "jargon 
                        name" for a conference, for example,
                        "Extreme" for "Extreme Markup Languages" or
                        "SIGGRAPH" for "Special Interest Group on 
                        Computer Graphics". Provided for searching
                        convenience when the jargon name is better
                        known that the full formal conference name.
                          Authoring and Conversion Note: A conference
                        acronym often includes the year of the 
                        conference (e.g. "SGML '97") or, less often, 
                        the conference number (e.g., "AMBA 6"). It 
                        is preferred, but not required, that the 
                        acronym exclude this year or number (thus
                        using "SGML" or "AMBA" and putting the year
                        or number in the <conf-date> and 
                        <conf-num> elements, respectively.         -->
<!ELEMENT  conf-acronym (#PCDATA %conf-acronym-elements;)*           >


<!--                    CONFERENCE NUMBER ELEMENTS                 -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the conference number.     
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an inline
                        mix, the OR bar is already there.          -->
<!ENTITY % conf-num-elements 
                        "%simple-text;"                              >
 

<!--                    CONFERENCE NUMBER                          -->
<!--                    The sequential number of the conference.
                        Authoring and Conversion Note: Ideally, the
                        conference number should include only the 
                        numeric portion of the number without any  
                        suffixes or other text. For example, "The 
                        19th XML/SGML Conference" should be tagged as 
                           <conf-num>19</conf-num> 
                        with the "th" dropped.                     -->
<!ELEMENT  conf-num     (#PCDATA %conf-num-elements;)*               >


<!--                    CONFERENCE SPONSOR  ELEMENTS               -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the conference sponsor. 
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an inline
                        mix, the OR bar is already there.          -->
<!ENTITY % conf-sponsor-elements 
                        "%simple-text;"                              >
 

<!--                    CONFERENCE SPONSOR                         -->
<!--                    One organization that sponsored the 
                        conference. If more than one organization
                        sponsored the conference, multiple 
                        <conf-sponsor> elements should be used.    -->
<!ELEMENT  conf-sponsor (#PCDATA %conf-sponsor-elements;)*           >


<!--                    CONFERENCE THEME ELEMENTS                  -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        the conference theme.         
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an online
                        mix, the OR bar is already there.          -->
<!ENTITY % conf-theme-elements 
                        "%simple-text;"                              >
 

<!--                    CONFERENCE THEME                           -->
<!--                    The theme, slogan, or major subject area of
                        the conference.  For example, the name of an
                        annual conference, may be "16th ACH Gathering"
                        but each year has a different theme topic,
                        such as "Database Integration" or "Topic
                        Map Subject Access".                       -->
<!ELEMENT  conf-theme   (#PCDATA %conf-theme-elements;)*             >


<!-- ============================================================= -->
<!--                    COUNTING INFORMATION (ARTICLE METADATA)    -->
<!-- ============================================================= -->


<!ENTITY % counts-model "(fig-count?, table-count?, equation-count?, 
                         ref-count?, page-count?, word-count?)"      >


<!--                    COUNTS                                     -->
<!--                    Wrapper element to hold all metadata that 
                        "counts how many of something appear in the 
                        article                                    -->
<!ELEMENT  counts       %counts-model;                               >


<!--                     EQUATION COUNT                            -->
<!--                     Number of display equations <disp-formula> 
                         that appear in the article. Inline-equations 
                         <inline-formula> are not counted. No 
                         distinction is made between numbered and 
                         unnumbered equations, both are counted.   -->
<!ELEMENT  equation-count 
                         EMPTY                                       >
<!--                     The "count" attribute indicates the number
                         of display equations <disp-formula> in the 
                         article. Inline-equations <inline-formula> 
                         are not counted. No distinction is made 
                         between numbered and unnumbered equations, 
                         both are counted.                         -->
<!ATTLIST  equation-count
            count        NMTOKEN                           #REQUIRED >


<!--                     FIGURE COUNT                              -->
<!--                     Number of Figures <fig> that appear in the
                         article. Loose <graphic>s that appear
                         outside figures are not counted.          -->
<!ELEMENT  fig-count     EMPTY                                       >
<!--                     The "count" attribute indicates the number
                         of figures in the article, that is, how
                         many <fig> elements are used              -->
<!ATTLIST  fig-count
            count        NMTOKEN                           #REQUIRED >


<!--                     TABLE COUNT                               -->
<!--                     Number of tables (Table Wrapper <table-wrap>
                         elements that appear in the article. Arrays 
                         are not counted as tables.                -->
<!ELEMENT  table-count   EMPTY                                       >
<!--                     The "count" attribute indicates the number
                         of tables in the article, that is, how
                         many <table-wrap> elements are used.      -->
<!ATTLIST  table-count
            count        NMTOKEN                           #REQUIRED >


<!--                     REFERENCE COUNT                           -->
<!--                     Number of reference citations <citation> 
                         that appear in the bibliographic reference 
                         list <ref-list> in the article            -->
<!ELEMENT  ref-count     EMPTY                                       >
<!--                     The "count" attribute indicates the number
                         of reference citations in the article     -->
<!ATTLIST  ref-count
            count        NMTOKEN                           #REQUIRED >


<!--                     PAGE COUNT                                -->
<!--                     Number of pages in a print article, counting
                         each page or partial page as one. Electronic
                         articles do not have page counts.         -->
<!ELEMENT  page-count    EMPTY                                       >
<!--                     The "count" attribute indicates the number
                         of pages in the article                   -->
<!ATTLIST  page-count
            count        NMTOKEN                           #REQUIRED >


<!--                     WORD COUNT                                -->
<!--                     Approximate number of words that appear in 
                         the article                               -->
<!ELEMENT  word-count    EMPTY                                       >
<!--                     The "count" attribute indicates the number
                         of  words in the textual portion of an 
                         article (not including the words in the 
                         metadata or header information)           -->
<!ATTLIST  word-count
            count        NMTOKEN                           #REQUIRED >



<!-- ============================================================= -->
<!--                    TITLE GROUP ELEMENTS (BIBLIOGRAPHIC)       -->
<!-- ============================================================= -->


<!--                    TITLE GROUP MODEL                          -->
<!--                    Content model for the <title-group> element-->
<!ENTITY % title-group-model   
                        "(article-title, subtitle*, trans-title*, 
                          alt-title*, fn-group?)"                    > 


<!--                    TITLE GROUP                                -->
<!--                    Wrapper element to hold the various article 
                        titles.
                        Authoring and Conversion Note: A footnote or 
                        other reference inside a title should usually 
                        be placed inside the title, but may be tagged
                        in a group at the end of the <title-group>, 
                        if that is the way they are in the source.)-->
<!ELEMENT  title-group  %title-group-model;                          >


<!--ELEM   article-title
                        Defined in %common.ent;                    -->
<!--ELEM   trans-title  Defined in %common.ent;                    -->
<!--ENTITY %title-elements;   
                        Defined in %common.ent;                    -->
                                                             

<!--                    ARTICLE SUBTITLE                           -->
<!ELEMENT  subtitle     (#PCDATA %title-elements;)*                  >


<!--                    ALTERNATE TITLE                            -->
<!--                    A "different" version of an article title,
                        usually created so that it can be processed 
                        in a special way, for example a short 
                        version of the title for use in a Table of 
                        Contents, an ASCII title, a right-running-
                        head title, etc.
                        Authoring and Conversion Note: This element
                        should not be used for either the translated 
                        title (which is an alternate version of a 
                        title in another language) or the subtitle
                        (which is an addition to the title).       -->
<!ELEMENT  alt-title    (#PCDATA %title-elements;)*                  >
<!--         alt-title-type
                        Why this title was created, for example,
                        "short" for a short version of the title,
                        "toc" for use in a Table of Contents, "ASCII" 
                        for an ASCII title, "right-running" for
                        a right-running-head title, etc.           -->
<!ATTLIST  alt-title
             %alt-title-atts;                                        >


<!-- ============================================================= -->
<!--                    CONTRIBUTOR GROUP (AUTHOR/EDITOR) ELEMENTS -->
<!-- ============================================================= -->


<!--                    CONTRIBUTOR GROUP MODEL                    -->
<!--                    Content model for the <contrib-group> 
                        element                                    -->
<!ENTITY % contrib-group-model   
                        "(contrib+, (%contrib-info.class;)* )"       > 


<!--                    CONTRIBUTOR GROUP                          -->
<!--                    Wrapper element for information concerning 
                        a grouping of contributors, such as the
                        primary authors                            -->
<!ELEMENT  contrib-group
                        %contrib-group-model;                        >


<!--                    CONTRIBUTOR MODEL                          -->
<!--                    Content model for the <contrib> element    -->
<!ENTITY % contrib-model  
                        "((%name.class;)*, 
                          (%degree.class; | %contrib-info.class;)* )">


<!--                    CONTRIBUTOR                                -->
<!--                    Wrapper element to contain the information
                        about a single contributor, for example an
                        author or editor.                   
                        Authoring and Conversion Note: Use <xref> 
                        to point to the institution <aff>, the
                        corresponding information <corresp>, and 
                        any author footnotes in the author note
                        group.
                        Conversion Note: When the ranking or 
                        importance of authors is marked as a note,
                        (for example, the ranking element in the 
                        Elsevier DTD), it should be encoded in the
                        role element. Thus, the Elsevier-tagged
                        text:
                          <ranking><sup>*</sup></ranking>
                        would be converted to:
                          <role><sup>*</sup></role>
                                                                   -->
<!ELEMENT  contrib      %contrib-model;                              >
<!--         contrib-type
                        What was the contribution of this person,
                        for example: author, editor, contributor,
                        translator, illustrator, designer, 
                        research assistant, etc.                 
             id         Unique identifier, so the contributor can be
                        referenced
             corresp    Corresponding Author (Set to 'yes' if this 
                        contributor is a corresponding author.)
             equal-contrib    
                        Contributed equally (Set to 'yes' if all 
                        contributors contributed equally.) 
             deceased   Deceased (Set to 'yes' if the contributor
                        has died.)                           
             rid        May be used to point to information concerning
                        the contributor, for example to the <corresp>
                        Corresponding Information element.  There
                        is no limit to the number of contributors 
                        that can be designated as corresponding.
             xlink:href Provides an address or identifier of the
                        object to which the link points, for
                        example a URI or a filename.               -->
<!ATTLIST  contrib
             %contrib-atts;                                          >



<!--ELEM  collab        Defined %common.ent; (also used in
                        bibliographic citations)                   -->
<!--ELEM  etal          Defined %common.ent; (also used in
                        bibliographic citations)                   -->


<!--                    DEGREE(S) ELEMENTS                         -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        <degrees>                             
                        Design Note: -%just-rendition; begins with
                        an OR bar, so this inline mix begins with
                        an OR bar.                                 -->
<!ENTITY % degrees-elements
                        "%just-rendition;"                           >


<!--                    DEGREE(S)                                  -->
<!--                    Academic degrees or professional
                        certifications                             -->
<!ELEMENT  degrees      (#PCDATA %degrees-elements;)*                >


<!--                    ON BEHALF OF CONTENT ELEMENTS              -->
<!--                    The elements that can be included along with
                        data characters inside the content model of
                        <on-behalf-of>                             
                        Design Note: -%rendition-plus; begins with
                        an OR bar, so this inline mix beguines with
                        an OR bar.                                 -->
<!ENTITY % on-behalf-of-elements
                        "%rendition-plus;"                           >


<!--                    ON BEHALF OF                               -->
<!--                    When a contributor has written or edited
                        a work  "on-behalf-of" an organization or 
                        group the contributor is acting as a
                        representative of the organization, which 
                        may or may not be his/her usual affiliation.
                        Related elements: Some DTDs identify this
                        category as a "collaboration", but it
                        is really more akin to a "role" the person
                        is playing with respect to the organization.
                        Thus this element joins the related
                        element <role> in describing the contribution
                        of a contributor. The <role> element will
                        say that a person is an "Editor" or 
                        "Associate Editor" and the <on-behalf-of>
                        element will state that this editing was
                        undertaken as a representative of a group
                        or organization:
                        <contrib> 
                             <name>
                               <surname>Campion</surname>
                               <given-names>M</given-names>
                             </name>
                             <on-behalf-of>for 
                             the Multiple Sclerosis Collaborative 
                             Research Group</on-behalf-of>
                          </contrib>
                           Conversion Note: In some DTDs, the 
                        association "on-behalf-of" may have been 
                        tagged as a <role> rather than as a
                        specific <on-behalf-of>.
                        It is therefore also acceptable although
                        not as accurate) to tag the example as: 
                           <contrib>
                             <name>
                               <surname>Campion</surname>
                               <given-names>M</given-names>
                             </name>
                             <role>for the Multiple 
                             Sclerosis Collaborative Research 
                             Group</role>
                           </contrib>                              -->
<!ELEMENT  on-behalf-of    
                        (#PCDATA %on-behalf-of-elements;)*           >


<!--                    AUTHOR COMMENT MODEL                       -->
<!--                    Content model for the <author-comment> 
                        element                                    -->
<!ENTITY % author-comment-model  
                        "(title?, (%just-para.class;)+ )"            >


<!--                    AUTHOR COMMENT                             -->
<!--                    Used for extra textual material associated 
                        with a contributor such as an author or
                        editor
                        Conversion Note: During conversion, this 
                        element can act as an escape mechanism, to
                        hold material not anticipated by the DTD.
                        The base model is just paragraphs, but this
                        model has been made into a Parameter Entity
                        in case a section level is needed.         -->
<!ELEMENT  author-comment    
                        %author-comment-model;                       >


<!-- ============================================================= -->
<!--                    SUPPLEMENT ELEMENTS                        -->
<!-- ============================================================= -->


<!--                    SUPPLEMENT ELEMENTS                        -->
<!--                    Elements for use in the <supplement> element
                        DESIGN NOTE: All inline mixes begin with an
                        OR bar, but since %simple-text; is an inline
                        mix, the OR bar is already there.          -->
<!ENTITY % supplement-elements 
                        "%simple-text;"                              > 


<!--                    SUPPLEMENT                                 -->
<!--                    For a journal published as a supplement, this
                        is a container element for all the provided
                        supplement information, such as additional
                        identification numbers, titles, and 
                        supplement series information.             -->
<!ELEMENT supplement    (#PCDATA %supplement-elements;)*             >
<!--        supplement-type   
                        Indicates what sort of supplement, if the
                        publisher has recorded that information,
                        for example: "issue" meaning a supplement to 
                        a particular journal issue; "conference", 
                        meaning the supplement contains information 
                        from a conference, symposium, or other 
                        gathering; "periodic" for supplements issued  
                        at regular intervals, etc.                 -->
<!ATTLIST supplement
            %supplement-atts;                                        >


<!-- ================== End Article Metadata Elements  =========== -->
