1.
Bushev DM, Kharkevych YI. Approximation of classes of periodic multivariable functions by linear positive operators. Ukr. Mat. Zhurn. [Internet]. 2006 Jan. 25 [cited 2025 Dec. 5];58(1):12–19. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/3430