History of Enigma Code in World War II

Colossus: Bletchley Park's Greatest Secret

By Gannon, Paul

Enigma: The Battle For The Code (Cassell Military Paperbacks)

By Hugh Sebag-Montefiore

The Ultra Secret

By Winterbotham, F.W.

X, Y & Z: The Real Story of How Enigma Was Broken

By Dermot Turing

Codebreakers: The Inside Story of Bletchley Park

By Hinsley, F. H., Stripp, Alan

Codebreakers: The Inside Story of Bletchley Park

By Hinsley, Sir F. H.