Marianne Hickey. <a href="http://www.w3.org/TR/2000/WD-multimodal-reqs-20000710"><cite>Multimodal Requirements for Voice Markup Languages.</cite></a> 10 July 2000. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2000/WD-multimodal-reqs-20000710">http://www.w3.org/TR/2000/WD-multimodal-reqs-20000710</a>