Anders Berglund. <a href="http://www.w3.org/TR/2006/REC-xsl11-20061205"><cite>Extensible Stylesheet Language (XSL) Version 1.1.</cite></a> 5 December 2006. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2006/REC-xsl11-20061205">http://www.w3.org/TR/2006/REC-xsl11-20061205</a>