ROMANYUK, A. S.; ROMANYUK, V. S. Estimates of some approximating characteristics of the classes of periodic functions of one and many variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 71, n. 8, p. 1102–1115, 2019. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1501. Acesso em: 14 apr. 2025.