KOSTICH, M. V. Approximation of functions from Weyl-Nagy classes by Zygmund averages. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 5, p. 735–738, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4912. Acesso em: 11 apr. 2025.