PAPAGEORGIOU, Nikolaos S.; VETRO, Calogero; VETRO, Francesca. Multiple nodal solutions for semilinear Robin problems with indefinite linear part and concave terms. Topological Methods in Nonlinear Analysis, [S. l.], v. 50, n. 1, p. 269–286, 2017. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2017.029. Acesso em: 8 jul. 2025.