1.
Machniak A. Polish military intelligence and counterintelligence activities against the Soviet Union 1918–1939: a description of operations from the files of the main directorate of information of the Polish army . Ur Jo of Huma and Soc Scie [Internet]. 2017 Apr. 1 [cited 2026 Nov. 12];2(1):27-43. Available from: https://journals.ur.edu.pl/jhss/article/view/124