Evtukhov, V. M., and A. A. Koz’ma. “Existence Criteria and Asymptotics for Some Classes of Solutions of Essentially Nonlinear Second-Order Differential Equations”. Ukrains’kyi Matematychnyi Zhurnal 63, no. 7 (July 25, 2011): 924-938. Accessed April 19, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2775.