VOITENKO, S. P. Best $M$-Term trigonometric approximations of the classes $B^{Ω}_{p,θ}$ of periodic functions of many variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 61, n. 9, p. 1189–1199, 2009. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3091. Acesso em: 5 dec. 2025.