D771m Deavours, Cipher A. and Kruh, Louis. Machine Cryptography and Modern Cryptanalysis . British Special Forces in North Africa, 1940-1943 . New York, Greenwood Press, 1987. The Road Watch and the Verification of Ultra, pp 131-154.
Book call no.
940.5423 G663o Intelligence and Military Operations , edited by Michael I. Handel. London, Frank Cass, 1990. Book call no. 355.3432 I61 Kahn, David. Boston, Houghton Mifflin Co, 1991.