SEVER, Y.; ALTAY, B. On the Core of Double Sequences. Sarajevo Journal of Mathematics, [S. l.], v. 11, n. 2, p. 273–282, 2024. DOI: 10.5644/SJM.11.2.13. Disponível em: https://sjm.anubih.ba/index.php/sjm/article/view/216. Acesso em: 15 oct. 2024.