1. Internet Engineering Task Force, RFC 1510: The Kerberos Network Authentication Service (V5) (September 1993)
2. Lecture Notes in Computer Science;A. Pashalidis,2003
3. http://www.projectliberty.org
4. http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=security
5. http://www.passport.com