Stasyuk, S.A. (2012) “Best approximation of periodic functions of several variables from the classes $MB^{\omega}_{p,\theta}$”, Ukrains’kyi Matematychnyi Zhurnal, 64(1), pp. 140–144. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2561 (Accessed: 10 April 2025).