FEDORENKO, A. S. Bestm-term trigonometric approximations of classes of (Ψ, β)-differentiable functions of one variable. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 52, n. 6, p. 850–855, 2000. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4482. Acesso em: 27 apr. 2025.