1. See Ross Anderson's posting on USENET newsgroup sci.crypt, “Subject: A5 (Was: HACKING DIGITAL PHONES)”, 17 Jun 1994,. Alternatively, S. B. Xu, D. K. He, and X. M. Wang, “An implementation of the GSM General Data Encryption Algorithm A5”, CHINACRYPT '94, Xidian, China, 11–15 November 1994, pp 287–291 (in Chinese). The latter appears to be based on the same information as Anderson's posting (or possibly the posting itself) as Anderson states that two of the registers have unknown polynomials, but the polynomials are the same in his posting and Xu et.al.
2. W. Caelli, E Dawson, L. Nielsen, H. Gustafson, “CRYPT-X Stastical Package Manual, Measuring the strength of Stream and Block Ciphers”, Queensland Univeristy of Technology, 1992, ISBN 0-86856-8090.
3. T. Herlestam, “On functions of Linear Shift Register Sequences”, in Franz Pichler, editor, Proc. EUROCRYPT 85, LNCS 219, Springer-Verlag 1986.
4. G. Marsaglia, “DIEHARD”, http://stat.fsu.edu/~geo/diehard.html
5. A. Menezes, P. Van Oorschot, S. Vanstone, “Handbook of Applied Cryptography”, CRC Press, 1997, Ch 6.