EVTUKHOV, V. M.; VLADOVA, E. S. Asymptotic representations of solutions of essentially nonlinear two-dimensional systems of ordinary differential equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 61, n. 12, p. 1597–1611, 2009. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3126. Acesso em: 6 dec. 2025.