GEDEON, T.; MISCHAIKOW, K. Singular boundary value problems via the Conley index. Topological Methods in Nonlinear Analysis, [S. l.], v. 28, n. 2, p. 263–283, 2006. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2006.030. Acesso em: 22 jul. 2024.