1. WS-Security,
http://msdn.microsoft.com/library/default.asp?url=/library/enus/dnglobspec/html/ws-security.asp
(last accessed: 23/9/2003)
2. XACML,
http://www.oasis-open.org/committees/xacml/repository/oasis-xacml-1.0.pdf
(last accessed: 23/9/2003)
3. Lecture Notes in Computer Science;J.H. Hine,2000