Khachatryan, Aghavard, and Khachatur Khachatryan. “On Solvability of One Infinite System of Nonlinear Functional Equations in the Theory of Epidemics”. Eurasian Mathematical Journal 11, no. 2 (May 29, 2024). Accessed January 21, 2025. https://emj.enu.kz/index.php/main/article/view/178.