Emily Candell; Jeff Hoepfinger. <a href="http://www.w3.org/TR/2008/WD-vxml30reqs-20080808"><cite>Voice Extensible Markup Language (VoiceXML) 3.0 Requirements.</cite></a> 8 August 2008. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2008/WD-vxml30reqs-20080808">http://www.w3.org/TR/2008/WD-vxml30reqs-20080808</a>