James Clark. <a href="http://www.w3.org/TR/1999/REC-xslt-19991116"><cite>XSL Transformations (XSLT) Version 1.0.</cite></a> 16 November 1999. W3C Recommendation. URL: <a href="http://www.w3.org/TR/1999/REC-xslt-19991116">http://www.w3.org/TR/1999/REC-xslt-19991116</a>