Klaas Bals. <a href="http://www.w3.org/TR/2008/WD-xslfo20-req-20080326"><cite>Extensible Stylesheet Language (XSL) Requirements Version 2.0.</cite></a> 26 March 2008. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2008/WD-xslfo20-req-20080326">http://www.w3.org/TR/2008/WD-xslfo20-req-20080326</a>