Romanyuk, A. S. 2016. “Entropy Numbers and the Widths of the Classes $B_{p,θ}^r$ of Periodic Functionsof Many Variables”. Ukrains’kyi Matematychnyi Zhurnal 68 (10), 1403-17. https://umj.imath.kiev.ua/index.php/umj/article/view/1928.