The battle of the Atlantic and signals intelligence : U-boat situations and trends, 1941-1945 - Syrett, David (Aldershot : Ashgate, 1998)
Keywords: World War, 1939-1945 -- Cryptography; World War, 1939-1945 -- Military intelligence; World War, 1939-1945 -- Naval operations -- Submarine; World War, 1939-1945 -- Naval operations, German; World War, 1939-1945 -- Campaigns -- Atlantic Ocean