HIRANO, N.; RYBICKI, S. Some remarks on degree theory for ${\text{\rm SO}(2)}$-equivariant transversal maps. Topological Methods in Nonlinear Analysis, [S. l.], v. 22, n. 2, p. 253–272, 2003. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2003.039. Acesso em: 22 jul. 2024.