FARBER, M. Zeros of closed 1-forms, homoclinic orbits and Lusternik-Schnirelman theory. Topological Methods in Nonlinear Analysis, [S. l.], v. 19, n. 1, p. 123–152, 2002. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2002.008. Acesso em: 27 apr. 2024.