VAKARCHUK, S. B.; SHCHITOV, A. N. On some extremal problems in the theory of approximation of functions in the spaces $S^p,\quad 1 \leq p < \infty$. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 58, n. 3, p. 303–316, 2006. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3455. Acesso em: 27 apr. 2025.