Oisin Hurley; et al. <a href="http://www.w3.org/TR/2003/NOTE-xmlp-reqs-20030728"><cite>XML Protocol (XMLP) Requirements.</cite></a> 28 July 2003. W3C Note. URL: <a href="http://www.w3.org/TR/2003/NOTE-xmlp-reqs-20030728">http://www.w3.org/TR/2003/NOTE-xmlp-reqs-20030728</a>