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Charles, Jean-Leon, and Philippe Dasnoy, Les Dossiers Secrets de la Police Allemande in Belgique, vol. 1: 1940-1942, vol. 2: 1942-1944, Brussels: Editions Arts & Voyages, 1972.
Krichbaum, Wilhelm, Secret Field Police: Wehrmacht Geheime Feldpolizei in World War II, 1939-1945, Historical Division, Headquarters United States Army in Europe, 1950 (German version was written in 1947).
WWII Netherlands Escape Lines 