Niewiński, Andrzej. “Individual Ransom As a Tool for Liberation of a Prisoner of War in Late Medieval Western Europe (11th–14th Centuries)”. Acta Universitatis Lodziensis. Folia Historica, no. 114 (October 19, 2023): 27–55. Accessed February 11, 2026. https://www.czasopisma.uni.lodz.pl/historica/article/view/19832.