Serdyuk, A. S. and Stepanets, O. I. (2002) “Direct and Inverse Theorems in the Theory of Approximation of Functions in the Space $S^p$”, Ukrains’kyi Matematychnyi Zhurnal, 54(1), pp. 106-124. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4044 (Accessed: 18May2024).