ROMANYUK, A. S.; YANCHENKO, S. Ya. Estimates of approximation characteristics and properties of operators of the best approximation for the classes of periodic functions in the space $B_{1,1}$. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 73, n. 8, p. 1102–1119, 2021. DOI: 10.37863/umzh.v73i8.6755. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/6755. Acesso em: 5 dec. 2025.