1. ISO/ITU-T Rec. X.509 (2000) The Directory: Authentication Framework
2. Chokhani, S., Ford, W. (1999) Internet X.509 Public Key Infrastructure Certificate Policy and Certification Practices Framework. RFC 2527. March 1999.
3. Manchala (2000) E-Commerce Trust Metrics and Models IEEE INTERNET COMPUTING March-April 2000 p. 36–44.
4. Basden, A., Brown, A. J. (1996) Istar — a tool for creative design of knowledge bases, Expert Systems, v. 13, n. 4, pp. 259–276, November 1996.
5. Basden, A., Ball, E., Chadwick, D. W. (2001) Issues Raised in Modelling Trust in a Public Key Infrastructure, Expert Systems, Vol 18, No. 5, (Nov 2001), pp. 233–249.