Michael F. Scholz, "Active measures and disinformation as part of East Germany's propaganda war, 1953–1972", in: Kristie Macrakis, Thomas Wegener Friis and Helmut Müller-Enbergs, ed., East German Foreign Intelligence: Myth, Reality and Controversy, Studies in intelligence series, London/New York: Routledge, 2010, ISBN9780415484428, pp. 113–, p. 116.
The International Journal of Intelligence and CounterIntelligence 1 (1986) 114.