MAWHIN, J.; RUIZ, D. A strongly nonlinear Neumann problem at resonance with restrictions on the nonlinearity just in one direction. Topological Methods in Nonlinear Analysis, [S. l.], v. 20, n. 1, p. 1–14, 2002. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2002.021. Acesso em: 25 apr. 2024.