KonohraiA. F. (2011) “Estimates for the approximate characteristics of the classes $B_{p, \theta}^{\Omega}$ of periodic functions of two variables with given majorant of mixed moduli of continuity”, Ukrains’kyi Matematychnyi Zhurnal, 63(2), pp. 176-186. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2709 (Accessed: 23November2024).