The SGML/XML Web Page
Database containing over 2000 documents pertaining to SGML, XML, and related standards. Features a bibliography for SGML, vendors and service providers, software reviews, mailing lists, user groups, and projects.

Graphic Communications Association
Supports and promotes SGML and related technologies in their efforts in advancing interoperability of information systems.

Overview of SGML Resources
SGML links at the W3C, meant for use in reviews of the HTML specification.

SP
A free, object-oriented toolkit for SGML parsing, validating, and entity management.

SGML on the Web
Circa 1995 list of SGML web sites, and resources for using SGML on the Web.

Women Writers Project, ACM Crossroads Winter 1999
This article from Crossroads Winter 1999 issue describes the use of SGML to encode literature archives for research, written by B. Fan.

SGML for NT
A brief tutorial how to set up a free SGML editing and publishing system for Windows NT. Encourages use of free software options.

GCA Registry of Owner Identifiers
Small database of globally registered SGML public identifiers.

Comparison of SGML and XML
A Note from the W3C detailing the differences and similarities between the two markup languages.

A Gentle Introduction to SGML
An SGML FAQ in the context of the TEI e-text initiative and SGML application.

SGMLtools-Lite
Formerly Linuxdoc-SGML, SGMLtools offers a out-of-the-box SGML processing solution for technical (DocBook) documentation. [Open source, GPL]

SGML: A Gentle Introduction
Tutorial from Text Encoding Initiative.