P. Leach; M. Mealling; R. Salz. <a href="http://www.ietf.org/rfc/rfc4122.txt"><cite>A Universally Unique IDentifier (UUID) URN Namespace</cite></a> July 2005. Internet RFC 4122. URL: <a href="http://www.ietf.org/rfc/rfc4122.txt">http://www.ietf.org/rfc/rfc4122.txt</a>