The Ultra secret - Winterbotham, F. W. (Frederick William), 1897-1990. (New York : Harper & Row, 1974)
HU OSA 300 - RFE/RL collection
Keywords: Winterbotham, F. W. -- 1897-1990.; World War, 1939-1945 -- Cryptography; World War, 1939-1945 -- Secret service -- Great Britain; World War, 1939-1945 -- Personal narratives, British