Vartanyan, Egnara G. “BULGARIA AND RUSSIA OF THE EARLY 20th CENTURY: FROM THE CORRESPONDENCE OF N. S. DERZHAVIN WITH BULGARIAN SCIENTISTS”. Zhurnal Belorusskogo Gosudarstvennogo Universiteta. Istoriya 6, no. 2 (May 17, 2024): 33–40. Accessed October 10, 2025. https://journals-bsu.com/index.php/history/article/view/46.