(en) Senate Select Committee to Study Governmental Operations with Respect to Intelligence Activities, Final report of the Select Committee to Study Governmental Operations with Respect to Intelligence Activities, Book I: Foreign and Military Intelligence, US Government Printing Office, 14 avril 1976, p. 194 [lire en ligne]
(en) Christoffer J. Henriksen, “I Was” : The Oleg Penkovsky Story and the Important of Human Intelligence in Cold War Crises (mémoire de licence d'histoire), Eau Claire, Wisconsin, University of Wisconsin-Eau Claire, (lire en ligne), p. 43
