SHAN, Yuan; LI, Keqiang. Index theory for linear elliptic equation and multiple solutions for asymptotically linear elliptic equation with resonance. Topological Methods in Nonlinear Analysis, [S. l.], v. 44, n. 1, p. 89–104, 2016. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2014.037. Acesso em: 4 jul. 2025.