From:  ftp://ftp.sol.no/public/users/v/vigu/sgml/dtd/bibtex/bibtex.dtd
See also: http://home.sol.no/~vigu/dtds.html
<!--

This DTD expresses SGML markup similar to the BibTeX language
specified for LaTeX, or actually its content model. For documentation
on BibTeX, see

  ftp://ftp.tex.ac.uk/tex-archive/biblio/bibtex/distribs/doc/

  Lamport, Leslie: LaTeX: A Document Preparation System,
  Addison-Wesley, 2nd edition, 1994

Suggested invocation:

  <!DOCTYPE btx-file PUBLIC "-//Oren Patashnik//DTD bibtex//EN" >

When used as a module within another DTD (e.g. ISO 12083):

     <!ENTITY % bibtex PUBLIC
      "-//Oren Patashnik//DTD bibtex//EN" "bibtex.dtd">
     %bibtex;
     <!ELEMENT bibliography   - O  (head?, btx-Entry)* >

This DTD is available from

  http://home.sol.no/~vigu/dtds.html

This code originally developed by
Vidar Bronken Gundersen (vidarg@bigfoot.com)
Reuse and repurposing is approved as long as this
notification appears with the code

Last modification 1998-12-18

Changelog:

1998-09-25: changed the content model for `InBook' (a and/or b)
1998-10-04: added common fields to all entries
1998-10-05: all element names changed to bib-xxxx
            changed the suggested invocation
            removed element bibliography
1998-12-05: all element names changed to btx-xxxx
1998-12-17: notified Oren Patashnik of this DTD

Planned improvements:

   o The common elements entity needs further thought

-->


<!-- ..................................................................... -->
<!-- Top elements, main structure -->

<!-- BiblioEntry (and n.Instance) is the element that contains all the
     others. -->

<!ENTITY   %  n.Instance "(btx-Article | btx-Book | btx-Booklet |
                    btx-Conference | btx-InBook | btx-InCollection |
                    btx-InProceedings | btx-Manual | btx-MastersThesis
                    | btx-Misc | btx-PHDThesis | btx-Proceedings |
                    btx-TechReport | btx-Unpublished )*">

<!ELEMENT btx-Entry         - -  (%n.Instance;) >
<!ATTLIST btx-Entry   ID     ID              #REQUIRED >

<!ELEMENT btx-File          - -  (btx-Entry)* >


<!-- ..................................................................... -->
<!-- Parameter entities for elements with similar content model -->

<!ENTITY   %  n.InProceedings "(btx-Author, btx-Title, btx-Booktitle,
                    btx-Year, btx-Editor?, (btx-Volume | btx-Number)?,
                    btx-Series?, btx-Pages?, btx-Address?, btx-Month?,
                    btx-Organization?, btx-Publisher?, btx-Note?)">

<!ENTITY   %  n.PHDThesis "(btx-Author, btx-Title, btx-School,
                    btx-Year, btx-Type?, btx-Address?, btx-Month?,
                    btx-Note?)">

<!ENTITY   %  n.common "(btx-Key?, btx-Annotate?, btx-Crossref?,
                    btx-Keywords?, (btx-ISSN | btx-ISBN)?, (btx-URL |
                    btx-URI | btx-URN)?)"
  -- these are additional elements often used, but not included in the
     standard BibTeX distribution, these must be added to the
     bibliography styles, otherwise these fields will be omitted by
     the formatter -->


<!-- ..................................................................... -->
<!-- Entries in the BibTeX database -->

<!ELEMENT   btx-Article  - -   (btx-Author, btx-Title, btx-Journal,
               btx-Year, btx-Volume?, btx-Number?, btx-Pages?,
               btx-Month?, btx-Note?, %n.common;)
  -- [article] An article from a journal or magazine.  Required
     fields: author, title, journal, year.  Optional fields: volume,
     number, pages, month, note. -->

<!ELEMENT   btx-Book  - -   ((btx-Author | btx-Editor), btx-Title,
               btx-Publisher, btx-Year, (btx-Volume | btx-Number)?,
               btx-Series?, btx-Address?, btx-Edition?, btx-Month?,
               btx-Note?, %n.common;)
  -- [book] A book with an explicit publisher.  Required fields:
     author or editor, title, publisher, year.  Optional fields:
     volume or number, series, address, edition, month, note. -->
	   
<!ELEMENT   btx-Booklet  - -   (btx-Author?, btx-Title,
               btx-HowPublished?, btx-Address?, btx-Month?, btx-Year?,
               btx-Note?, %n.common;)
  -- [booklet] A work that is printed and bound, but without a named
     publisher or sponsoring institution.  Required field: title.
     Optional fields: author, howpublished, address, month, year,
     note. -->

<!ELEMENT   btx-Conference  - -     (%n.InProceedings;)
  -- [conference] The same as INPROCEEDINGS, included for Scribe
     compatibility. -->

<!ELEMENT   btx-InBook  - -   ((btx-Author | btx-Editor), btx-Title,
                    ((btx-Chapter , btx-Pages?) | btx-Pages),
                    btx-Publisher, btx-Year, (btx-Volume |
                    btx-Number)?, btx-Series?, btx-Type?,
                    btx-Address?, btx-Edition?, btx-Month?, btx-Note?,
                    %n.common;)
  -- [inbook] A part of a book, which may be a chapter (or section or
     whatever) and/or a range of pages.  Required fields: author or
     editor, title, chapter and/or pages, publisher, year.  Optional
     fields: volume or number, series, type, address, edition, month,
     note. -->

<!--
> I want to express that the elements a and/or b are legal that is one
> of them or both must be present in the document instance (see the
> element content for BibTeX entry `InBook').
> How do I specify this in my DTD?

        in content model:     ((a , b?) | b)     if order matters
                              ((a , b?) | (b , a?))     otherwise

Dave Peterson
-->

<!ELEMENT   btx-InCollection  - -   (btx-Author, btx-Title,
                    btx-BookTitle, btx-Publisher, btx-Year,
                    btx-Editor?, (btx-Volume | btx-Number)?,
                    btx-Series?, btx-Type?, btx-Chapter?, btx-Pages?,
                    btx-Address?, btx-Edition?, btx-Month?, btx-Note?,
                    %n.common;)
  -- [incollection] A part of a book having its own title.  Required
     fields: author, title, booktitle, publisher, year.  Optional
     fields: editor, volume or number, series, type, chapter, pages,
     address, edition, month, note. -->

<!ELEMENT   btx-InProceedings  - -     (%n.InProceedings;)
  -- [inproceedings] An article in a conference proceedings.  Required
     fields: author, title, booktitle, year.  Optional fields: editor,
     volume or number, series, pages, address, month, organization,
     publisher, note. -->

<!ELEMENT   btx-Manual  - -   (btx-Author?, btx-Title,
               btx-Organization?, btx-Address?, btx-Edition?,
               btx-Month?, btx-Year?, btx-Note?, %n.common;)
  -- [manual] Technical documentation.  Required field: title.
     Optional fields: author, organization, address, edition, month,
     year, note. -->

<!ELEMENT   btx-MastersThesis  - -     (%n.PHDThesis;)
  -- [mastersthesis] A Master's thesis.  Required fields: author,
     title, school, year.  Optional fields: type, address, month,
     note. -->

<!ELEMENT   btx-Misc  - -   (btx-Author?, btx-Title?,
               btx-HowPublished?, btx-Month?, btx-Year?, btx-Note?,
               %n.common;)
  -- [misc] Use this type when nothing else fits.  Required fields:
     none.  Optional fields: author, title, howpublished, month, year,
     note. -->

<!ELEMENT   btx-PHDThesis  - -     (%n.PHDThesis;)
  -- [phdthesis] A PhD thesis.  Required fields: author, title,
     school, year.  Optional fields: type, address, month, note. -->

<!ELEMENT   btx-Proceedings  - -   (btx-Editor?, btx-Title, btx-Year,
               (btx-Volume | btx-Number)?, btx-Series?, btx-Address?,
               btx-Month?, btx-Organization?, btx-Publisher?,
               btx-Note?, %n.common;)
  -- [proceedings] The proceedings of a conference.  Required fields:
     title, year.  Optional fields: editor, volume or number, series,
     address, month, organization, publisher, note. -->

<!ELEMENT   btx-TechReport  - -   (btx-Author, btx-Title,
               btx-Institution, btx-Year, btx-Type?, btx-Number?,
               btx-Address?, btx-Month?, btx-Note?, %n.common;)
  -- [techreport] A report published by a school or other institution,
     usually numbered within a series.  Required fields: author,
     title, institution, year.  Optional fields: type, number,
     address, month, note. -->

<!ELEMENT   btx-Unpublished  - -   (btx-Author, btx-Title, btx-Note,
               btx-Month?, btx-Year?, %n.common;)
  -- [unpublished] A document having an author and title, but not
     formally published.  Required fields: author, title, note.
     Optional fields: month, year. -->


<!-- ..................................................................... -->
<!-- Fields from the standard bibliography styles -->

<!ELEMENT   btx-Address       - -   (#PCDATA) >
<!ELEMENT   btx-Author        - -   (#PCDATA) >
<!ELEMENT   btx-BookTitle     - -   (#PCDATA) >
<!ELEMENT   btx-Chapter       - -   (#PCDATA) >
<!ELEMENT   btx-Edition       - -   (#PCDATA) >
<!ELEMENT   btx-Editor        - -   (#PCDATA) >
<!ELEMENT   btx-HowPublished  - -   (#PCDATA) >
<!ELEMENT   btx-Institution   - -   (#PCDATA) >
<!ELEMENT   btx-Journal       - -   (#PCDATA) >
<!ELEMENT   btx-Month         - -   (#PCDATA) >
<!ELEMENT   btx-Note          - -   (#PCDATA) >
<!ELEMENT   btx-Number        - -   (#PCDATA) >
<!ELEMENT   btx-Organization  - -   (#PCDATA) >
<!ELEMENT   btx-Pages         - -   (#PCDATA) >
<!ELEMENT   btx-Publisher     - -   (#PCDATA) >
<!ELEMENT   btx-School        - -   (#PCDATA) >
<!ELEMENT   btx-Series        - -   (#PCDATA) >
<!ELEMENT   btx-Title         - -   (#PCDATA) >
<!ELEMENT   btx-Type          - -   (#PCDATA) >
<!ELEMENT   btx-Volume        - -   (#PCDATA) >
<!ELEMENT   btx-Year          - -   (#PCDATA) >

<!-- These were not listed in the documentation for entry content, but
     appeared in the list of fields in the BibTeX documentation -->

<!ELEMENT   btx-Annotate      - -   (#PCDATA) >
<!ELEMENT   btx-Crossref      - -   (#PCDATA) >
<!ELEMENT   btx-Key           - -   (#PCDATA) >

<!--
Below is a description of all fields recognized by the standard
bibliography styles.  An entry can also contain other fields, which
are ignored by those styles.

[address] Usually the address of the publisher or other type of
institution.  For major publishing houses, van~Leunen recommends
omitting the information entirely.  For small publishers, on the other
hand, you can help the reader by giving the complete address.

[annote] An annotation.  It is not used by the standard bibliography
styles, but may be used by others that produce an annotated
bibliography.

[author] The name(s) of the author(s), in the format described in the
LaTeX book.

[booktitle] Title of a book, part of which is being cited.  See the
LaTeX book for how to type titles.  For book entries, use the title
field instead.

[chapter] A chapter (or section or whatever) number.

[crossref] The database key of the entry being cross referenced.

[edition] The edition of a book-for example, ``Second''.  This
should be an ordinal, and should have the first letter capitalized, as
shown here; the standard styles convert to lower case when necessary.

[editor] Name(s) of editor(s), typed as indicated in the LaTeX book.
If there is also an author field, then the editor field gives the
editor of the book or collection in which the reference appears.

[howpublished] How something strange has been published.  The first
word should be capitalized.

[institution] The sponsoring institution of a technical report.

[journal] A journal name.  Abbreviations are provided for many
journals; see the Local Guide.

[key] Used for alphabetizing, cross referencing, and creating a label
when the ``author'' information (described in Section [ref: ] is
missing. This field should not be confused with the key that appears
in the \cite command and at the beginning of the database entry.

[month] The month in which the work was published or, for an
unpublished work, in which it was written.  You should use the
standard three-letter abbreviation, as described in Appendix B.1.3 of
the LaTeX book.

[note] Any additional information that can help the reader.  The first
word should be capitalized.

[number] The number of a journal, magazine, technical report, or of a
work in a series.  An issue of a journal or magazine is usually
identified by its volume and number; the organization that issues a
technical report usually gives it a number; and sometimes books are
given numbers in a named series.

[organization] The organization that sponsors a conference or that
publishes a manual.

[pages] One or more page numbers or range of numbers, such as 42-111
or 7,41,73-97 or 43+ (the `+' in this last example indicates pages
following that don't form a simple range).  To make it easier to
maintain Scribe-compatible databases, the standard styles convert a
single dash (as in 7-33) to the double dash used in TeX to denote
number ranges (as in 7-33).

[publisher] The publisher's name.

[school] The name of the school where a thesis was written.

[series] The name of a series or set of books.  When citing an entire
book, the the title field gives its title and an optional series field
gives the name of a series or multi-volume set in which the book is
published.

[title] The work's title, typed as explained in the LaTeX book.

[type] The type of a technical report-for example, ``Research
Note''.

[volume] The volume of a journal or multivolume book.

[year] The year of publication or, for an unpublished work, the year
it was written.  Generally it should consist of four numerals, such as
1984, although the standard styles can handle any year whose last four
nonpunctuation characters are numerals, such as `(about 1984)'.
-->

<!-- ..................................................................... -->
<!-- Local fields -->

<!ELEMENT   btx-ISBN          - -   (#PCDATA) >
<!ELEMENT   btx-ISSN          - -   (#PCDATA) >
<!ELEMENT   btx-Keywords      - -   (#PCDATA) >
<!ELEMENT   btx-URL           - -   (#PCDATA) >
<!ELEMENT   btx-URI           - -   (#PCDATA) >
<!ELEMENT   btx-URN           - -   (#PCDATA) >


<!-- ..................................................................... -->
<!-- End of bibtex.dtd -->