Motornyi, V. P. (2001) “On Exact Estimates for the Pointwise Approximation of the Classes $W^rH^ω$ by Algebraic Polynomials”, Ukrains’kyi Matematychnyi Zhurnal, 53(6), pp. 783-799. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4299 (Accessed: 19May2024).