This primary source comes from the Records of the Central Intelligence Agency.
Full Citation: East Central Europe De Facto Territorial Arrangements July 1941 through June 1943; 4/1947; Published Maps, 1947 - 2015; Records of the Central Intelligence Agency, Record Group 263; National Archives at College Park, College Park, MD. [Online Version, https://www.docsteach.org/documents/document/east-central-europe-1941-1943-map, May 15, 2024]