Steven Pemberton. <a href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/"><cite>XHTML&#8482; 1.0 The Extensible HyperText Markup Language (Second Edition).</cite></a> 1 August 2002. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2002/REC-xhtml1-20020801/">http://www.w3.org/TR/2002/REC-xhtml1-20020801/</a>