Engel, David (1983). "An Early Account of Polish Jewry under Nazi and Soviet Occupation Presented to the Polish Government-In-Exile, February 1940". Jewish Social Studies. 45 (1): 1–16. ISSN0021-6704. JSTOR4467201.
From an 5 April 2015 interview with Waldemar Kowalski of the Polish Press Agency, as quoted in Grudzinska-Gross, Irena (2016). "Polishness in Practice". In Irena Grudzinska-Gross; Iwa Nawrocki (eds.). Poland and Polin: New Interpretations in Polish-Jewish Studies. Frankfurt a.M: Peter Lang. p. 37. ISBN978-3-653-96123-2. Retrieved 22 November 2019.
Engel, David (1983). "An Early Account of Polish Jewry under Nazi and Soviet Occupation Presented to the Polish Government-In-Exile, February 1940". Jewish Social Studies. 45 (1): 1–16. ISSN0021-6704. JSTOR4467201.