ОМАРОВА , Б. . MULTIPERIODIC SOLUTIONS OF SECOND-ORDER SYSTEMS WITH DIFFERENTIATION OPERATOR ON THE LYAPUNOV’S VECTOR FIELD . Bulletin of the Abai KazNPU, the series of "Physical and Mathematical Sciences", Алматы, Казахстан, v. 69, n. 1, p. 155–163, 2021. Disponível em: https://bulletin-phmath.kaznpu.kz/index.php/ped/article/view/235. Acesso em: 3 jul. 2024.