American Memory DTD for Historical Documents

In its presentation of historical collections, the Library of Congress uses Standard Generalized Markup Language (SGML) for two types of documents: finding aids and the full texts of books, pamphlets, manuscripts, and other historical texts. Examples of finding aids that conform to the emerging standard for Encoded Archival Description are available online. Marked-up pamphlet, broadside, manuscript, and book texts are available for a number of collections; see, for example, the National American Woman Suffrage Collection or the George Washington Papers.

http://memory.loc.gov/ammem/techdocs/amdtd.html