Voitovych, V. A. “Estimates for the Approximations of the Classes of Analytic Functions by Interpolation Analogs of the De-La-Vallée–Poussin Sums”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 1 (January 25, 2014): 49–62. Accessed April 23, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2110.