GRAVEN, Andrew; HUBBARD, John. An elementary proof of Poincaré’s last geometric theorem. Pro Mathematica, [S. l.], v. 31, n. 62, p. 61–93, 2021. Disponível em: https://revistas.pucp.edu.pe/index.php/promathematica/article/view/23436. Acesso em: 23 dic. 2025.