Hojdis, B. 1997. The life and problems connected with Władysław Warneńczyk (of Varna) in the literary creation of Leopold Kielanowski. Balcanica Posnaniensia. Acta et studia. 8, (Aug. 1997), 201–208. DOI:https://doi.org/10.14746/bp.1997.8.17.