XHTML 1.0 Specification
W3C specification for XHTML 1.0.

Building XHTML Modules
Working draft. Defines how XHTML modules can be built.

XHTML Basic
A W3C specification for a minimal subset of Modular XHTML.

XHTML 1.1 Specification
W3C specification for XHTML 1.1.

Modularization of XHTML
W3C specification for Modular XHTML.

Ruby Annotation
"Ruby" are short runs of text alongside the base text, typically used in East Asian documents to indicate pronunciation or to provide a short annotation. This specification defines markup for ruby, in the form of an XHTML module. (W3C Recommendation 31 May 2001)

XHTML Events
An updated events syntax for XHTML and friends. (W3C Working Draft 08 June 2001)

XHTML 1.0 (Second Edition)
W3C specification for XHTML 1.0 (2nd Ed.) (W3C Working Draft 4 October 2001).

Modularization of XHTML
Specifies an abstract modularization of XHTML and an implementation of the abstraction using XML Document Type Definitions (DTDs).

Modularization of XHTML in XML Schema
A methodology for the modularization of XHTML using XML Schema. It allows document authors to modify and extend XHTML in a conformant way.

HLink
Module providing link recognition for the XHTML Family.