CANNON, J.W.; FLOYD, W.J.; PARRY, W.R. Sufficiently rich families of planar rings. Annales Fennici Mathematici, [S. l.], v. 24, n. 2, p. 265–304, 1999. Disponível em: https://afm.journal.fi/article/view/134954. Acesso em: 12 dec. 2025.