Document Type Definitions (DTDs)

Document Type Definitions (DTDs) for both SGML and XML are similar. This page contains Web resources for SGML and XML DTDs. All links will open a new browser window.

• Defining SGML Document Structures: The Document Type Definition (DTD) -- part of the Hyperlib Electronic Document Store, this document is the first page of a tutorial-like section on DTDs in an SGML manual.
• A Document Type Declaration for Formal Metadata -- a well-documented SGML DTD conforming to the Content Standards for Digital Geospatial Metadata of the Federal Geographic Data Committee.
• How to Read the HTML DTD -- part of the official W3C HTML 4.0 specification, this page is devoted to reading the DTD on which the markup language is based.
• SGML Exceptions and XML -- created by Eve Maler, this paper discusses SGML exceptions and why XML does not allow exceptions.
• Snafu Document Type Declaration -- the formal SGML syntax declaration for 3 types of technical papers.
• DITA (Darwin Information Typing Architecture) XML DTD -- This is a new, up and coming standard for information that is topic-oriented. It is well-supported with many unique public-domain tools in the user community. The link to this DTD is Robin Cover's page on DITA, an excellent starting point.
  
• TEI Guidelines for Electronic Text Encoding and Interchange -- this 41-page document describes the structure of a SGML DTD including several examples. Thanks to Mark Conrad of NHPRC for pointing out the Model Editions Partnership at the University of South Carolina. The markup guidelines and reference manual on that page show some useful additions to TEI for historical documents.