Frederick Hirsch; Mike Just. <a href="http://www.w3.org/TR/2003/NOTE-xkms2-req-20030505"><cite>XML Key Management (XKMS 2.0) Requirements.</cite></a> 5 May 2003. W3C Note. URL: <a href="http://www.w3.org/TR/2003/NOTE-xkms2-req-20030505">http://www.w3.org/TR/2003/NOTE-xkms2-req-20030505</a>