VAKARCHUK, B. S. Jackson-type inequalities with generalized modulus of continuity and exact values of the $n$-widths for the classes of $(ψ,β)$-differentiable functions in $L_2$. III. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 68, n. 10, p. 1299–1319, 2016. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1922. Acesso em: 14 apr. 2025.