1. Kohnfelder, L.: Towards a practical public-key cryptosystem. PhD thesis, Massachusetts Institute of Technology (1978)
2. ISO: ISO/IEC 9594-8 - Information technology — Open Systems Interconnection — The Directory: Public key and attribute certificate frameworks. ISO (2008)
3. Adams, C., Cain, P., Pinkas, D., Zuccherato, R.: Internet X.509 Public Key Infrastructure Time-Stamp Protocol (TSP). RFC 3161 (Proposed Standard) (August 2001) Updated by RFC 5816
4. Comodo: The Recent RA Compromise, http://blogs.comodo.com/it-security/data-security/the-recent-ra-compromise/ (visited November 2011)
5. h online: Attack on Israeli Certificate Authority, http://h-online.com/-1264008 (visited November 2011)