Evtukhov, V. M., and O. R. Shlepakov. “Asymptotic Representations of Solutions of Essentially Nonlinear Systems of Ordinary Differential Equations With Regularly and Rapidly Varying Nonlinearities”. Ukrains’kyi Matematychnyi Zhurnal 64, no. 9 (September 25, 2012): 1165-1185. Accessed March 28, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2650.