1. ITU. Recommendation X.509, The Directory: Authentication Framework (also ISO/IEC 9594-8, 1995). International Telecommunications Union, Telecommunication Standardization Sector(ITU-T) (1993)
2. ITU. Recommendation X.500, Data Communication Network Directory. International Telecommunications Union, Telecommunication Standardization Sector(ITU-T) (1993)
3. ITU. Recommendation X.509, The Directory: Abstract Service Definition (also ISO/IEC 9594-3, 1995). International Telecommunications Union, Telecommunication Standardization Sector(ITU-T) (1993)
4. Wahl, M., Howes, T., Kille, S.: RFC 2251 - Lightweight Directory Access Protocol Version 3 (LDAPv3). IETF (December 1997)
5. Housley, R., Ford, W., Polk, W., Solo, D.: RFC 2459 - Internet X.509 Public Key Infrastructure, Certificate and CRL Profile. IETF (January 1999)