VETRO, C.; WARDOWSKI, D. Krasnosel’skii-Schaefer type method in the existence problems. Topological Methods in Nonlinear Analysis, [S. l.], v. 54, n. 1, p. 131–139, 2019. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2019.028. Acesso em: 22 jul. 2024.