A. F. Konohrai, “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”, Ukr. Mat. Zhurn., vol. 63, no. 2, pp. 176–186, Feb. 2011, Accessed: Feb. 15, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2709