Notes
- Erskine , R. 1986 . ‘GC&CS Mobilizes “Men of the Professor Type” ‘ . Cryptologia , 10 ( 1 ) : 50 – 9 .
- Hinsley , F. H. 1981 . British Intelligence in the Second World War , Vol. 2 , London : HMSO .
- Hinsley , F. H. and Stripp , A. , eds. 1993 . Codebreakers , Oxford : Oxford University Press .
- Calvocoressi , P. London 1980 . Top Secret Ultra , London , Cassell .
- Bennett , R. 1979 . Ultra in the West , London : Hutchinson .
- Milner‐Barry , P.S. 1986 . ‘"Action This Day”: The Letter from the Bletchley Park Cryptanalysts to the Prime Minister, 21 October 1941’ . Intelligence and National Security , 1 ( 2 ) : 272 – 6 .
- Welchman , Gordon . 1982 . The Hut Six Story , London : Allen Lane .
- Winterbotham , F. W. 1974 . The Ultra Secret , London : Weidenfeld & Nicholson .
- Lewin , R. 1978 . Ultra Goes to War , London : Hutchinson .
- West , Nigel . 1986 . G.C.H.Q. , London : Weidenfeld & Nicolson .