Vakarchuk M. B., and VakarchukS. B. “On Total Moduli of Continuity for $2\pi$-Periodic Functions of Two Variables in the Space $L_{2,2}$”. Ukrains’kyi Matematychnyi Zhurnal 69, no. 3 (March 25, 2017): 300-310. Accessed July 27, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/1697.