Serdyuk AS, Stepanets OI. Direct and Inverse Theorems in the Theory of Approximation of Functions in the Space $S^p$. Ukr. Mat. Zhurn. [Internet]. 2002Jan.25 [cited 2024Nov.22];54(1):106-24. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/4044