Hrissimov, Nikolay. “Some Questions about the Slavic Tribes That Participated in the Anti-Bulgarian Uprisings Along the Mid-Danube in the First Decades of the 9th Century”. Studia Ceranea 12 (November 21, 2022): 465–489. Accessed May 3, 2024. https://www.czasopisma.uni.lodz.pl/sceranea/article/view/15551.