JAFARI, S. On certain types of notions via preopen sets. Tamkang Journal of Mathematics, [S. l.], v. 37, n. 4, p. 391–398, 2006. DOI: 10.5556/j.tkjm.37.2006.152. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/152. Acesso em: 19 apr. 2024.