PRYKARPATSKY, A. K.; SAMOILENKO, A. M.; TIMCHISHIN, O. Ya. The Poincare-Mel’nikov geometric analysis of the transversal splitting of manifolds of slowly perturbed nonlinear dynamical systems. I. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 12, p. 1668–1681, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5975. Acesso em: 5 dec. 2025.