K. Karun; Mary F. Fern&#225;ndez; Mark Scardina. <a href="http://www.w3.org/TR/2005/WD-xpath20req-20050603"><cite>XPath Requirements Version 2.0.</cite></a> 3 June 2005. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2005/WD-xpath20req-20050603">http://www.w3.org/TR/2005/WD-xpath20req-20050603</a>