PERERA, K.; SCHECHTER, M. Type II regions between curves of the Fučik spectrum and critical groups. Topological Methods in Nonlinear Analysis, [S. l.], v. 12, n. 2, p. 227–243, 1998. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1998.039. Acesso em: 26 apr. 2024.