VANNELLA, G. Morse theory applied to a $T^{2}$-equivariant problem. Topological Methods in Nonlinear Analysis, [S. l.], v. 17, n. 1, p. 41–53, 2001. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2001.003. Acesso em: 19 jul. 2024.