EVTUKHOV, V. M.; BELOZEROVA, M. A. Asymptotic representations of the solutions of essentially nonlinear nonautonomous second-order differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 3, p. 310–331, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3158. Acesso em: 5 dec. 2025.