CALDAS, Miguel; NAVALAGI, Govindappa. On generalizing ?-open functions. Pro Mathematica, [S. l.], v. 22, n. 43-44, p. 103–121, 2008. Disponível em: https://revistas.pucp.edu.pe/index.php/promathematica/article/view/10259. Acesso em: 23 dic. 2025.