Kuznetsova О. I. Strong Karleman averages of multiple trigonometric Furier series. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 2, p. 275–279, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/7842. Acesso em: 6 dec. 2025.