CHABROWSKI, J.; GIRĀO, P. M. On the exterior Neumann problem involving the critical Sobolev exponent. Topological Methods in Nonlinear Analysis, [S. l.], v. 23, n. 1, p. 33–43, 2004. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2004.002. Acesso em: 20 jan. 2022.