1. Carrara, J., Legaspi, L.E.: SIM Cards: At the Heart of Digital Wireless Security. Annual Review of Communications 54, 1–10 (2001)
2. Chan, S.-C: An Overview of Smart Card security (1997), http://home.hkstar.com/~alanchan/papers/smartCardSecurity/
3. Chaum, D., Fiat, A., Naor, N.: Transaction Systems To Make Big Brother Obsolete. Communications of the ACM 28(5), 1030–1044 (1985)
4. Lecture Notes in Computer Science;D. Chaum,1988
5. Chaum, D.: An introduction to ecash: DigiCash (1995), http://www.digicash.com