RUDYAK, Y. B.; SCHLENK, F. Lusternik-Schnirelmann theory for fixed points of maps. Topological Methods in Nonlinear Analysis, [S. l.], v. 21, n. 1, p. 171–194, 2003. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2003.011. Acesso em: 22 feb. 2024.