Accessibility Richtlinien

Web Content Accessibility Guidelines (WCAG)
http://www.w3.org/WAI/intro/wcag.php
Authoring Tool Accessibility Guidelines (ATAG)
http://www.w3.org/WAI/intro/atag.php
User Agent Accessibility Guidelines (UAAG)
http://www.w3.org/WAI/intro/uaag.php