RomanyukA. S. (1994) “On Kolmogorov widths of classes $B^r_{p, \theta}$ of periodic functions of many variables with low smoothness in the space $L_q$”, Ukrains’kyi Matematychnyi Zhurnal, 46(7), pp. 915–926. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5683 (Accessed: 6October2024).