PRECUP, R. A Granas type approach to some continuation theorems and periodic boundary value problems with impulses. Topological Methods in Nonlinear Analysis, [S. l.], v. 5, n. 2, p. 385–396, 1995. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1995.027. Acesso em: 22 jul. 2024.