ShabozovM. S. (2011) “Exact Jackson - Stechkin-type inequalities for 2π -periodic functions in <i>L </i><sub>2 </sub&gt; and widths of some classes of functions”, Ukrains’kyi Matematychnyi Zhurnal, 63(10), pp. 1434-1440. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2816 (Accessed: 23November2024).