Ignat’evA. O. (2015) “Bounds for the Periods of Periodic Solutions of Ordinary Differential Equations”, Ukrains’kyi Matematychnyi Zhurnal, 67(11), pp. 1569-1573. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2090 (Accessed: 23November2024).