FENG, Y.; TONG, P. Existence and nonexistence of positive periodic solutions to a differential inclusion. Topological Methods in Nonlinear Analysis, [S. l.], v. 42, n. 2, p. 449–459, 2013. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2013.045. Acesso em: 24 apr. 2024.