KUZNETSOVCI, O. I. Strong summability of multiple Fourier series and Sidon-type inequalities. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 12, p. 1630–1635, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4782. Acesso em: 27 apr. 2025.