Seizing the Enigma -- the race to break the German U-boat Codes, 1939-1943.
Houghton-Mifflin Boston MA 1991, 336 pages, index, notes, bibliography, photographs.
Houghton-Mifflin Boston MA 1991, 336 pages, index, notes, bibliography, photographs.
ACM and The Computer History Museum NY 1997, 414 pages, full page color photographs/portraits; index, sources etc.
John Wiley & Sons, NY 1960, eighth printing 1965; 293 pages, index, double-column text, diagrams, references.