Сергеевич Добровольский, Иван. “The Heterogeneity of the Prologue Text, As Shown by Orthographic Data”. Slavistica Vilnensis 53, no. 2 (December 1, 2004): 35–51. Accessed November 10, 2025. https://www.zurnalai.vu.lt/slavistica-vilnensis/article/view/26863.