LESZKA, Mirosław J. (ED.). The Bulgarian State in 927-969. The Epoch of Tsar Peter I: No. XXXIV. Poland: Lodz University Press,2018. DOI: 10.18778/8142-115-7. Disponível em: https://www.press.uni.lodz.pl/index.php/wul/catalog/book/1057. Acesso em: 21 jan. 2026.