Г. А. Хабургаев, “The Reform of Old Slavonic in Preslav School of Simeon”, KLB, vol. 39, no. 2, pp. 4–12, Dec. 1988, Accessed: Oct. 27, 2025. [Online]. Available: https://test.zurnalai.vu.lt/kalbotyra/article/view/31059