MOTA, M. C.; REZENDE, A. C.; SCHLOMIUK, D.; VULPE, N. Geometric analysis of quadratic differential systems with invariant ellipses. Topological Methods in Nonlinear Analysis, [S. l.], v. 59, n. 2A, p. 623–685, 2022. DOI: 10.12775/TMNA.2021.063. Disponível em: https://apcz.umk.pl/TMNA/article/view/37960. Acesso em: 22 jul. 2024.