STASYUK, S. A. Best Approximations and Kolmogorov and Trigonometric Widths of the Classes $B_{p,θ}^{Ω}$ of Periodic Functions of Many Variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 56, n. 11, p. 1557–1568, 2004. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3865. Acesso em: 27 apr. 2025.