GRZESIK, Ryszard. The heroes of Great Moravia – native or foreign?. Balcanica Posnaniensia. Acta et studia, [S. l.], v. 15, p. 53–64, 2009. DOI: 10.14746/bp.2009.15.6. Disponível em: https://pressto.amu.edu.pl/index.php/bp/article/view/53086. Acesso em: 5 aug. 2026.