GIAMBÒ, R.; GIANNONI, F.; PICCIONE, P.; TAUSK, D. V. Morse theory for normal geodesics in sub-Riemannian manifolds with codimension one distributions. Topological Methods in Nonlinear Analysis, [S. l.], v. 21, n. 2, p. 273–291, 2003. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2003.016. Acesso em: 19 apr. 2024.