SHAKIR, Qays Rashid. Minimal and Maximal Beta Open Sets. Al-Nahrain Journal of Science, [S. l.], v. 17, n. 1, p. 160–166, 2018. Disponível em: https://anjs.edu.iq/index.php/anjs/article/view/494. Acesso em: 22 may. 2026.