SROKA, Stanisław. Was Władysław Opolczyk the godfather of Władysław Jagiełło?. Our Past, [S. l.], v. 74, p. 297–300, 1990. DOI: 10.52204/np.1990.74.297-300. Disponível em: https://ojs.academicon.pl/np/article/view/7066. Acesso em: 9 nov. 2026.