1. GCHQ (1945), General Report on Tunny, p. 327, (this internal GCHQ report of 1945 was unsigned but is attributed to Good, I.J., Michie, D. and Timms, G.), available in the National Archives, Richmond, HW, p. 25.
2. Turing, A.M. (1936), “On computable numbers, with an application to the Entscheidungsproblem”, Proc. Lond. Math. Soc., Vol. 42 No. 2, pp. 230‐65.
3. Turing, A.M. (1938), “Systems of logic based on ordinals”, Proc. Lond. Math. Soc., Vol. 45 No. 2, pp. 161‐228, This was his PhD thesis, Princeton University, Princeton, NJ, 1939.
4. I.—COMPUTING MACHINERY AND INTELLIGENCE