PÖTZSCHE, C.; SIEGMUND, S. $C^{m}$-smoothness of invariant fiber bundles. Topological Methods in Nonlinear Analysis, [S. l.], v. 24, n. 1, p. 107–145, 2004. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2004.021. Acesso em: 25 apr. 2024.