ANDRES, J.; GÓRNIEWICZ, L. From the Schauder fixed-point theorem to the applied multivalued Nielsen theory. Topological Methods in Nonlinear Analysis, [S. l.], v. 14, n. 2, p. 229–238, 1999. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1999.030. Acesso em: 26 jan. 2022.