LIN, Huei-li; WAG, Hwai-chiuan; WU, Tsung-fang. A Palais-Smale approach to Sobolev subcritical operators. Topological Methods in Nonlinear Analysis, [S. l.], v. 20, n. 2, p. 393–407, 2002. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2002.042. Acesso em: 8 jul. 2025.