ROMANYUK, A. S. On the best approximations and Kolmogorov widths of besov classes of periodic functions of many variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 47, n. 1, p. 79–92, 1995. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5385. Acesso em: 6 dec. 2025.