EL-MONSEF, M. E. A.; KOZAE, A. M.; ABO-KHADRA, A. A. EXTENSIONS GENERATED BY CLOSED SETS. Tamkang Journal of Mathematics, [S. l.], v. 24, n. 2, p. 189–193, 1993. DOI: 10.5556/j.tkjm.25.1994.4488. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4488. Acesso em: 19 apr. 2024.