GABOR, Dorota. Remarks to the orientation and homotopy in coincidence problems involving Fredholm operators of nonnegative index. Topological Methods in Nonlinear Analysis, [S. l.], v. 31, n. 1, p. 161–190, 2008. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2008.009. Acesso em: 8 jul. 2025.