Sukhorolskyi, M.A. (1997) “On the order of local approximation of functions by trigonometric polynomials that are partial sums of averaging operators”,
Ukrains’kyi Matematychnyi Zhurnal, 49(5), pp. 706–714. Available at:
https://umj.imath.kiev.ua/index.php/umj/article/view/5052 (Accessed: 10 April 2025).