XING, Q. Maslov index for heteroclinic orbits of non-Hamiltonian systems on a two-dimensional phase space. Topological Methods in Nonlinear Analysis, [S. l.], v. 59, n. 1, p. 113–130, 2022. DOI: 10.12775/TMNA.2021.005. Disponível em: https://apcz.umk.pl/TMNA/article/view/37617. Acesso em: 3 jul. 2024.