Suleimenov Ж., and Kuanysh С.Қ. “ON THE EXISTENCE OF A CONDITIONALLY PERIODIC SOLUTION OF A QUASILINEAR SYSTEM DIFFERENTIAL EQUATION IN THE CRITICAL CASE”. Bulletin of Abai KazNPU. Series of Physical and Mathematical sciences 72, no. 4 (December 29, 2020): 56–62. Accessed December 15, 2025. https://bulletin-phmath.kaznpu.kz/index.php/ped/article/view/75.