Schecter, Jerrold L.; Deriabin, Peter S. The Spy Who Saved the World: How a Soviet Colonel Changed the Course of the Cold War. New York: C. Scribner's Sons. 1992: 284. ISBN 978-0-684-19068-6.
Oleg Gordievsky and Christopher Andrew (1990). KGB: The Inside Story. Hodder & Stoughton. ISBN0-340-48561-2; cited from Russian edition of 1999, pp. 476-79