Sams Teach Yourself Web Publishing with HTML and CSS in One Hour a Day (5th Edition)

PHP

http://www.php.net/

The CGI specification

http://hoohoo.ncsa.uiuc.edu/cgi/interface.html

ASP.NET

http://www.asp.net/

The original NCSA CGI documentation

http://hoohoo.ncsa.uiuc.edu/cgi/

CGI.pm

http://search.cpan.org/dist/CGI.pm/