EvtukhovV. M., and Kas’yanovaV. A. “Asymptotic Behavior of Unbounded Solutions of Essentially Nonlinear Second-Order Differential Equations. I”. Ukrains’kyi Matematychnyi Zhurnal 57, no. 3 (March 25, 2005): 338–355. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3602.