German concentration camps: Auschwitz, Oranienburg, Mauthausen and Dachau in "The Polish White Book", New York (1941). Halina Krahelska report from Auschwitz Oświęcim, pamiętnik więźnia ("Auschwitz: Diary of a prisoner"), 1942. "The Mass Extermination of Jews in German Occupied Poland", a paper issued by the Polish government-in-exile addressed to the United Nations, 1942