HAI, D. D. On singular nonpositone semilinear elliptic problems. Topological Methods in Nonlinear Analysis, [S. l.], v. 32, n. 1, p. 41–47, 2008. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2008.034. Acesso em: 27 apr. 2024.