Glenn Adams. <a href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427"><cite>Timed Text (TT) Authoring Format 1.0 Use Cases and Requirements.</cite></a> 27 April 2006. W3C Note. URL: <a href="http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427">http://www.w3.org/TR/2006/NOTE-ttaf1-req-20060427</a>