STEPANETS, O. I. Approximation Characteristics of the Spaces $S_p^{ϕ}$ in Different Metrics. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 53, n. 8, p. 1121–1146, 2001. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4331. Acesso em: 14 apr. 2025.