<!-- ============================================================= -->
<!--  MODULE:    Custom Special Characters Module                  -->
<!--  VERSION:   2.3                                               -->
<!--  DATE:      February 2007                                     -->
<!--                                                               -->
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<!-- ============================================================= -->
<!--                    PUBLIC DOCUMENT TYPE DEFINITION            -->
<!--                        TYPICAL INVOCATION                     -->
<!--
"-//NLM//DTD Archiving and Interchange DTD Suite Custom Special Characters Module v2.3 20070202//EN"
     Delivered as file "chars.ent"                                 -->
<!-- ============================================================= -->

<!-- ============================================================= -->
<!-- SYSTEM:     Archiving and Interchange DTD Suite               -->
<!--                                                               -->
<!-- PURPOSE:    XML special character entities                    -->
<!--                                                               -->
<!-- CONTAINS:   1) Definitions of DTD-specific and custom         -->
<!--                special characters (as general entities        -->
<!--                defined as hexadecimal or decimal character    -->
<!--                entities - Unicode numbers)                    -->
<!--                                                               -->
<!-- REQUESTS FOR DTD CHANGES:                                     -->
<!--             Send email to: pmc@ncbi.nlm.nih.gov               -->
<!--                                                               -->
<!-- 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 2.3                       (DAL/BTU) v2.3 (2007-02-02)
     
     Enhancement Release (2.3) following the Working Group meetings 
     of Oct-Nov/2006-Jan/2007. No backward-incompatible changes.
     Archiving loosened even more. New structures for all the DTDs. 
     
  3. Updated public identifier to "v2.3 20070202//EN"          

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

  2. Updated public identifier to "v2.3 20070202"          

     =============================================================
     Version 1.1                            (TRG) v1.1 (2003-11-01)

  1. Modified content model of element <private-char> so that 
     the element <inline-graphic> could be used multiple times.
     Rationale: A series of <inline-graphic> elements may occur in 
     the same content, especially if they are variants of one graphic, 
     and may be linked, with only one variation being displayed.
                                                                   -->


<!-- ============================================================= -->
<!--                    DESIGN COMMENT                             -->
<!-- ============================================================= -->
<!--                    This DTD Suite has been designed with Unicode
                        as the basic representation of all special
                        characters. The use of combining characters 
                        is supported and encouraged as is the use
                        of entities defined by the STIX project
                        (http://www.ams.org/STIX/). Unicode values
                        in planes other than Plane 0 may be freely
                        used.
                        
                        Use of private publisher entities and Unicode
                        Private Use Area is discouraged, but supported
                        with the <private-char> element, for which a
                        corresponding bitmap must be submitted.
                        
                        In cases where an entity name has been generally
                        accepted with a corresponding Unicode number
                        and the entity has not been added to
                        the ISO standard entity sets, a named entity
                        may be defined below (e.g. &euro;).
                        
                        Because of the potential for conflicts in
                        assignments by different publishers,
                        the Archival and Interchange DTD Suite does 
                        not support assignment of values in the
                        Unicode Private Use Area.
                        Publishers who have defined characters in the
                        Private Use Area must remap those characters
                        to existing Unicode values (using combining
                        characters for special accented characters
                        where appropriate), or must submit bitmaps of
                        those characters using one of the two methods
                        supported under the <private-char> element.
                        
                        Those custom publisher entities for which 
                        corresponding Unicode values have not been 
                        determined must be tagged with the 
                        <private-char> element. Publishers must submit 
                        bitmaps of those characters using one of the 
                        two methods supported in the <private-char> 
                        element.                                   -->

<!-- ============================================================= -->
<!--                    COMMONLY ACCEPTED ENTITIES FOR UNICODE 
                        GLYPHS                                     -->
<!-- ============================================================= -->

<!--                    For each of the following entities a name
                        and a Unicode numerical character reference
                        is given. Where a unique Unicode character 
                        could be determined, that character was used.
                        For some of the symbols combining characters
                        have been used. Do not use this space to
                        redefine characters already found in standard
                        ISO entity sets. Do not use this space to
                        define any character that cannot be 
                        represented with Unicode.                  -->

<!--                    LATIN SMALL LETTER G WITH CARON            -->
<!ENTITY  gcaron        "&#x01E7;"                                   >


<!--                    LATIN CAPITAL LETTER H WITH MACRON         -->
<!ENTITY  Hmacr         "&#x0048;&#x0304;"                           >


<!--                    EURO CURRENCY                              -->
<!ENTITY  euro          "&#x20AC;"                                   >


<!--                    FRANC CURRENCY                             -->
<!ENTITY  franc         "&#x20A3;"                                   >


<!-- ============================================================= -->
<!--                    PRIVATE USE AREA AND CUSTOM CHARACTERS     -->
<!-- ============================================================= -->
<!--
                        Special characters defined by publishers as
                        custom entities or in the Unicode Private Use
                        Area may not be deposited as is. If they
                        cannot be remapped to existing Unicode values,
                        they must be submitted as a bitmap using
                        the <private-char> element. The most 
                        repository-friendly technique is <glyph-data> 
                        although individual bitmap files may be 
                        submitted with inline-graphic.

                        We would like to thank Beacon Publishing and
                        the APS (American Physical Society) for 
                        providing us with this technique.          -->


<!--                    PRIVATE CHARACTER (CUSTOM OR UNICODE)      -->
<!--                    A custom character entity defined by a
                        publisher or a custom character from the
                        Unicode private-use area for which a bitmap
                        is submitted for the glyph.

                        Since there are no completely standard/public
                        agreements on how such characters are to be
                        named and displayed, this technique is to be
                        used instead of a custom general entity 
                        reference, to provide complete information 
                        on the intended character.
                        A document should contain a <private-char> 
                        element at each location where a private 
                        character is used within the document. The 
                        corresponding image for the glyph may be 
                        given in the <glyph-data> element or as an 
                        external bitmap file referenced by an 
                        <inline-graphic> element.

                        Implementation Note: <inline-graphic> should
                        only be used outside <private-char> when the
                        graphic is something other than a special
                        character.                                 -->
<!ELEMENT  private-char ((glyph-data | glyph-ref) | inline-graphic*) >
<!--         description
                        A human-readable description of the
                        character, for example, "Arrow, normal 
                        weight, single line, two-headed, Northwest 
                        to Southeast". 
             name       Unique name for the character in all 
                        uppercase ASCII, similar to names found 
                        in Unicode standard (e.g., "NORTHWEST 
                        SOUTHEAST ARROW"                           -->
<!ATTLIST  private-char
             description
                        CDATA                              #IMPLIED
             name       CDATA                              #IMPLIED  >


<!--                    GLYPH DATA FOR A PRIVATE CHARACTER         -->
<!--                    This element is used when there is known to
                        be no font available to render the private
                        character. The <glyph-data> element can be
                        used to provide information on the actual
                        glyph that is associated with the private-use
                        character. The element includes an inline
                        bitmap of the glyph encoded in plain
                        PBM (Plain Bit Map) format so that it is
                        human-readable.

                        For example:
                        <private-char name="NORTHWEST SOUTHEAST ARROW"
                        description="Arrow, normal weight, single
                        line, two-headed, Northwest to Southeast">
                        <glyph-data format="PBM" resolution="300"
                        x-size="34" y-size="34">
                        0000000000000000000000000000000000
                        0111111111111100000000000000000000
                        0111111111111100000000000000000000
                        0111110000000000000000000000000000
                        0111110000000000000000000000000000
                        0111111000000000000000000000000000
                        0110111100000000000000000000000000
                        0110011110000000000000000000000000
                        0110001111000000000000000000000000
                        0110000111100000000000000000000000
                        0110000011110000000000000000000000
                        0110000001111000000000000000000000
                        0110000000111100000000000000000000
                        0110000000011110000000000000000000
                        0110000000001111000000000000000000
                        0110000000000111100000000000000000
                        0110000000000011110000000000000000
                        0000000000000001111000000000000000
                        0000000000000000111100000000000110
                        0000000000000000011110000000000110
                        0000000000000000001111000000000110
                        0000000000000000000111100000000110
                        0000000000000000000011110000000110
                        0000000000000000000001111000000110
                        0000000000000000000000111100000110
                        0000000000000000000000011110000110
                        0000000000000000000000001111000110
                        0000000000000000000000000111100110
                        0000000000000000000000000011110110
                        0000000000000000000000000001111110
                        0000000000000000000000000001111110
                        0000000000000000011111111111111110
                        0000000000000000011111111111111110
                        0000000000000000000000000000000000
                        </glyph-data></private-char>               -->
<!ELEMENT  glyph-data   (#PCDATA)                                    >
<!--         id         Identifier so that the full glyph data need
                        not be repeated every time the character is
                        used. The <glyph-ref> element can be used
                        to point to this ID, to reuse a character
                        in subsequent text. If a character is not
                        reused, it need not be given an "id"
                        attribute.
             format     An optional attribute that names the image
                        format of the bitmap. Should be "PBM" if the
                        plain bitmap is included inline, so that the
                        plain text bitmap will be a human-readable
                        matrix of zeros and ones.
             resolution Resolution of the bitmap in dots per inch,
                        expressed as a decimal integer (e.g. 72, 300)
             x-size     Number of pixels per row in the bit-mapped 
                        glyph
             y-size     Number of rows of the bit-mapped glyph     -->
<!ATTLIST  glyph-data
             id         ID                                 #IMPLIED
             format     NMTOKEN                            #IMPLIED
             resolution CDATA                              #IMPLIED
             x-size     CDATA                              #IMPLIED
             y-size     CDATA                              #IMPLIED  >


<!--                    GLYPH REFERENCE FOR A PRIVATE CHARACTER    -->
<!--                    Once a private character has been declared
                        using a <glyph-data> element, the character
                        can be reused by using this element to 
                        point to the full <glyph-data> element.
                        The pointing uses the ID/IDREF mechanism,
                        using the "glyph-data" attribute of this
                        element to point to the "id" attribute of 
                        another <glyph-data> element.              -->
<!ELEMENT  glyph-ref    EMPTY                                        >
<!--         glyph-data An IDREF-type attribute that points to the
                        "id" attribute of a <glyph-data> character.
                        The idea is to use the full glyph data once,
                        then point to an existing character instead 
                        of repeating the entire glyph data again.  -->
<!ATTLIST  glyph-ref
             glyph-data IDREF                              #IMPLIED  >

<!-- ================== End Custom XML Special Characters ======== -->
