CGI
http://hoohoo.ncsa.uiuc.edu/cgi/interface.html
MIME (RFC1341)[1]
http://www.w3.org/hypertext/WWW/Protocols/rfc1341/0_TableOfContents.html
HTML
http://www.w3.org/hypertext/WWW/MarkUp/HTML.html
HTML 2.0 and 3.0
ftp://www.ics.uci.edu/pub/ietf/html/index.html
Netscape Extensions to HTML
http://home.netscape.com/assist/net_sites/html_extensions.html
HTTP 1.0
http://www.w3.org/hypertext/WWW/Protocols/HTTP/HTTP2.html
URL
http://www.w3.org/hypertext/WWW/Addressing/Addressing.html
Footnotes:
[1] RFC1341 has been made obsolete by RFC1521; there is (as of this printing) no version of the new specification online. Check the above URL for the new specification as it becomes available.