Patrick Ion; David Carlisle. <a href="http://www.w3.org/TR/2008/WD-xml-entity-names-20080721"><cite>XML Entity definitions for Characters.</cite></a> 21 July 2008. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2008/WD-xml-entity-names-20080721">http://www.w3.org/TR/2008/WD-xml-entity-names-20080721</a>