Marinow, Kirił. “Foreign Policy”. In The Bulgarian State in 927-969. The Epoch of Tsar Peter I: No. XXXIV, edited by Mirosław J. Leszka, 111–135. Byzantina Lodziensia. Poland: Lodz University Press, 2018. Accessed January 21, 2026. https://www.press.uni.lodz.pl/index.php/wul/catalog/book/1057/chapter/2728.