Paul L. Kesaris (Hg.): The Rote Kapelle: the CIA's history of Soviet intelligence and espionage networks in Western Europe, 1936-1945. University, Washington D. C. 1979, S. 185. https://archive.org/details/rotekapelleci00unit
Paul L. Kesaris (Hg.): The Rote Kapelle: the CIA's history of Soviet intelligence and espionage networks in Western Europe, 1936-1945. University, Washington D. C. 1979, S. 193. https://archive.org/details/rotekapelleci00unit
