MARTÍNEZ-ALFARO, J.; MEZA-SARMIENTO, I. S.; OLIVEIRA, R. D. S. Singular levels and topological invariants of Morse--Bott foliations on non orientable surfaces. Topological Methods in Nonlinear Analysis, [S. l.], v. 51, n. 1, p. 183–213, 2018. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2017.051. Acesso em: 1 may. 2024.