SGML/XML constructs consist of Document Type Definitions (DTD), XML Stylesheet Language (XSL) , XML Stylesheet Language — Formatting Object (XSL-FO), Formatting Output Specification Instance (FOSI) or Document Style Semantics & Specification Language (DSSSL) and SGML/XML tag definitions. You can obtain all MIL-STD-2361 constructs from this site, however, you must obtain a library card first.
How to get a library card (required to download SGML/XML constructs).