KÖNIG, M. On Juliusz Schauder’s paper on linear elliptic differential equations. Topological Methods in Nonlinear Analysis, [S. l.], v. 11, n. 2, p. 351–360, 1998. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1998.022. Acesso em: 3 jul. 2024.