[[ENEV 94]

Ted Enever:

Britain's Best Kept Secret

Ultra Base at Bletchley Park

Alan Sutton Publishing Ltd., Printed in Great Britain, 1994.

 

[[ERDSUR 96] 

Erdős Pál, 

Surányi János:

Válogatott fejezetek a számelméletből    (in Hungarian)

(Selected chapters from the theory of numbers)

Polygon, Szeged, 1996.

 

 

[ESSI 96]

J. Essinger:

Computer Security within Financial Institutions

Financial Times, Financial Publishing, 1996.