HTML 2.0 Specification
Historical RFC1866 HTML 2.0 specification is discussed.
Hypertext Markup Language - 2.0
A detailed list of HTML tags.
ISO HTML 4 Specification
International standard for HTML 4.0, which is a refinement of W3C's HTML 4.0 standard.
OOPWeb: Markup Language Specifications
Covers markup language specifications for HTML 4.01, CSS2, XHTML 1.0, and XML 1.0.
Uniform Resource Locator Specs: rfc 1808
Specifications for webpage URLs.