Joss Pearson (ed.), Neil Webster's Cribs for Victory: The Untold Story of Bletchley Park's Secret Room

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Notes

¹ TNA PRO: HW 43/63, ‘GC&CS Sixta History: An Account of the Work of the Traffic Analysis Party at Bletchley Park’.

² However, Alexander may have been involved with the US Navy's Op-20-G in the design of Duenna for the same purpose. The US Army's Sigint Agency invented an electronic ‘Superscritcher’ to solve ‘D’.

³ ‘From Polish Bomba to British Bombe: The birth of Ultra’, Intelligence and National Security 1/1 (1986) pp.71–110.

⁴ Christopher Andrew, ‘Gordon Welchman, Sir Peter Marychurch and “The Birth of Ultra”’, Intelligence and National Security 1/2 (1986) pp.277–80.