1. West, N. 1986.GCHQ: The Secret Wireless War, 112London: Weidenfeld & Nicolson.
2. Andrew, C.M. 1985.Secret Service: The Making of the British Intelligence Community, 488London: Heinemann.
3. Bamford, J. 1982.The Puzzle Palace: America's National Security Agency and its Special Relationship with GCHQ, 313–14. London: Sidgwick & Jackson.
4. British Signals Intelligence after the Second World War