GABOR, D.; KRYSZEWSKI, W. A coincidence theory involving Fredholm operators of nonnegative index. Topological Methods in Nonlinear Analysis, [S. l.], v. 15, n. 1, p. 43–59, 2000. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2000.004. Acesso em: 29 mar. 2024.