Yangi versiyali Enigma mashinasini ishlash prinspi

1. 
   David Kahn, The Codebreakers
   1967. pp. 192-195.
   
2. 
   Mavis Batey, Dilly, The Man Who Broke Enigmas
   2009. Hard cover, ISBN 978-1-906447-01-4.
   
3. 
   Frode Weierud, Personal correspondence
   August 2017.
   
4. 
   Dennis Richie, Dabbling in the Cryptographic World - A Story
   Updated 5 May 2000. Retrieved November 2011.
   
5. 
   Collection of M-209 patent and license agreements
   A66684. Declassified by NSA on 11 June 2014 (EO 13526). 
   
6. 
   Jean-Francois Bouchaudy, M-209 Cryptanalysis
   Retrieved July 2016.
   

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