Masayasu Ishikawa. <a href="http://www.w3.org/TR/2002/NOTE-xhtml1-schema-20020902"><cite>XHTML 1.0 in XML Schema.</cite></a> 2 September 2002. W3C Note. URL: <a href="http://www.w3.org/TR/2002/NOTE-xhtml1-schema-20020902">http://www.w3.org/TR/2002/NOTE-xhtml1-schema-20020902</a>