Kowalska, Anna. “The Papal Appeals to Poland for Help the Holy Land (XIIth-XIVth с.)”. Acta Universitatis Lodziensis. Folia Historica, no. 67 (January 1, 2000): 129–145. Accessed December 9, 2025. https://www.czasopisma.uni.lodz.pl/historica/article/view/20994.