RAJMAN, Jerzy. The formation of Racibórz and Opole Duchy From the first division of Silesia in the second half of the 12th century. Wieki Stare i Nowe, [S. l.], v. 3, n. 8, p. 59–88, 2011. DOI: 10.31261/WSN.2011.11.04. Disponível em: https://journals.us.edu.pl/index.php/WSN/article/view/20391. Acesso em: 15 nov. 2026.