Jelaskan Lihat pula dari Oleg Penkovsky

Note: The book was commissioned by the Central Intelligence Agency see . A 1976 Senate commission stated that "the book was prepared and written by witting agency assets who drew on actual case materials." See  Author Frank Gibney denied the CIA had forged the provided source material, which was also the opinion of Robert Conquest. Other dismissed the book as propaganda and having no historic value.

Jerrold L. Schecter and Peter S. Deriabin, The Spy Who Saved the World: How a Soviet Colonel Changed the Course of the Cold War, New York, Charles Scribner's Sons, 1992.

Robert Wallace and H. Keith Melton, with Henry R. Schlesinger, Spycraft: The Secret History of the CIA's Spytechs, from Communism to al-Qaeda, New York, Dutton, 2008.

Frederick Forsyth, The Deceiver, Bantam Books, 1992 , p. 43, 4th line.

Viktor Suvorov, Devil's Mother, Sofia, Fakel Express, 2011 , in Bulgarian language.