Seizing the enigma : the race to break the German U-boat codes, 1939-1943 - Kahn, David, 1930- (Boston : Houghton Mifflin Co., 1991)
"A Thomas Congdon book"--T.p. verso.
Includes bibliographical references (p. [311]-326) and index.
Keywords: World War, 1939-1945 -- Cryptography; World War, 1939-1945 -- Naval operations, German; World War, 1939-1945 -- Naval operations -- Submarine; World War, 1939-1945 -- Naval operations -- Submarine