Bagieński, Witold. “Categories of Cases and Operational Documentation of the Ministry of the Interior Intelligence (1956-1990)”. Aparat Represji w Polsce Ludowej 1944-1989, no. 1(17) (March 28, 2023): 171–195. Accessed July 3, 2024. https://czasopisma.ipn.gov.pl/index.php/arpl/article/view/1625.