RUDYAK, Y. B.; TRALLE, A. On symplectic manifolds with aspherical symplectic form. Topological Methods in Nonlinear Analysis, [S. l.], v. 14, n. 2, p. 353–362, 1999. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1999.038. Acesso em: 18 apr. 2024.