ZHANG, Z.; CHENG, X. Existence of positive solutions for a semilinear elliptic system. Topological Methods in Nonlinear Analysis, [S. l.], v. 37, n. 1, p. 103–116, 2011. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2011.005. Acesso em: 20 apr. 2024.