“Estimates of the Orthogonal Widths of the Classes $B^{\Omega}_{\infty,\theta}$ of Periodic Functions of Many Variables With Given Majorant of the Mixed Moduli of Continuity”. Transactions of Institute of Mathematics, the NAS of Ukraine, vol. 12, no. 4, July 2015, pp. 205-1, https://trim.imath.kiev.ua/index.php/trim/article/view/294.