TONKES, Elliot. A semilinear elliptic equation with convex and concave nonlinearities. Topological Methods in Nonlinear Analysis, [S. l.], v. 13, n. 2, p. 251–271, 1999. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1999.013. Acesso em: 8 jul. 2025.