AL-SHARIF, Sh.; AL-QAHTANI, M. SOME PROPERTIES OF A NEW KIND OF DOWNWARD SETS IN CERTAIN BANACH SPACES. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 37, p. 402–413, 2017. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6793. Acesso em: 16 sep. 2026.