BARTSCH, Thomas; WANG, Zhi-Qiang. On the existence of sign changing solutions for semilinear Dirichlet problems. Topological Methods in Nonlinear Analysis, [S. l.], v. 7, n. 1, p. 115–131, 1996. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1996.005. Acesso em: 8 jul. 2025.