1. The 3rd Generation Partnership Project (3GPP), http://www.3gpp.org/
2. Lecture Notes in Computer Science;E. Biham,2000
3. Lecture Notes in Computer Science;A. Biryukov,2000
4. Lecture Notes in Computer Science;A. Biryukov,2001
5. M. Briceno, I. Goldberg, D. Wagner, A pedagogical implementation of the GSM A5/1 and A5/2 voice privacy encryption algorithms, (1999), http://cryptome.org/gsm-a512.htm , originally on www.scard.org