Wołoszyn, J. “‘Live Weapon’ – Undercover Agents in Prison Cells: Secret Collaborators in Prisons and Investigative Jails in the Years 1944–1956”. Remembrance and Justice, vol. 16, no. 2, Dec. 2010, pp. 295-37, https://czasopisma.ipn.gov.pl/index.php/pis/article/view/435.