NURAY, F.; PATTERSON, R. F. Submatrices of four dimensional summability matrices. CUBO, A Mathematical Journal, [S. l.], v. 17, n. 2, p. 89–95, 2015. DOI: 10.4067/S0719-06462015000200006. Disponível em: https://cubo.ufro.cl/ojs/index.php/cubo/article/view/1181. Acesso em: 19 may. 2024.