Richard Schwerdtfeger; Michael Cooper; Lisa Pappas. <a href="http://www.w3.org/TR/2008/WD-wai-aria-primer-20080204"><cite>WAI-ARIA Primer.</cite></a> 4 February 2008. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2008/WD-wai-aria-primer-20080204">http://www.w3.org/TR/2008/WD-wai-aria-primer-20080204</a>