Evtukhov, V. M., and KorepanovaЕ. S. “Asymptotic Representation of Solutions of Differential equations with Rightly Varying Nonlinearities”. Ukrains’kyi Matematychnyi Zhurnal 69, no. 9 (September 25, 2017): 1198-1216. Accessed October 2, 2022. http://umj.imath.kiev.ua/index.php/umj/article/view/1770.