FRANCA, M. Non-autonomous quasilinear elliptic equations and Ważewski’s principle. Topological Methods in Nonlinear Analysis, [S. l.], v. 23, n. 2, p. 213–238, 2004. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2004.010. Acesso em: 22 jan. 2022.