Difference Sequence Spaces of Second Order Defined by a Sequence of Moduli. Global Journal of Science Frontier Research, [S. l.], v. 21, n. F4, p. 27–35, 2021. Disponível em: https://www.journalofscience.org/index.php/GJSFR/article/view/3018. Acesso em: 14 aug. 2026.