FONDA, Alessandro; KLUN, Giuliano. On the topological degree of planar maps avoiding normal cones. Topological Methods in Nonlinear Analysis, [S. l.], v. 53, n. 2, p. 825–845, 2019. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2019.034. Acesso em: 8 jul. 2025.