VAKARCHUK, S. B. Exact values of mean $n$-widths for the classes of functions analytic in the upper half plane in the Hardy space. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 7, p. 814–824, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5672. Acesso em: 6 dec. 2025.