Konohrai, A. 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), 176-186. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/2709