ROMANYUK, A. S. Best approximations of the classes $B_{p,\,\theta}^{r}$ of periodic functions of many variables in uniform metric. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 58, n. 10, p. 1395–1406, 2006. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3541. Acesso em: 7 apr. 2025.