Leszka, Mirosław Jerzy. “The Rebellion of John Against Tsar Peter (928) Re-Discussed”. Balcanica Posnaniensia. Acta et studia 23 (January 26, 2017): 5–14. Accessed April 24, 2024. https://pressto.amu.edu.pl/index.php/bp/article/view/6692.