LAL, S.; TRIPATHI, V. N. On the study of double Fourier series by double matrix summability method. Tamkang Journal of Mathematics, [S. l.], v. 34, n. 1, p. 1–16, 2003. DOI: 10.5556/j.tkjm.34.2003.267. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/267. Acesso em: 29 mar. 2024.