“Lebesgue Type Inequalities for the de la Vallée Poussin Sums and Their Interpolation Analogues on Classes of $(\psi,\bar{\beta})$-Differentiable Functions”. Transactions of Institute of Mathematics, the NAS of Ukraine 10, no. 1 (July 15, 2013): 39–58. Accessed September 9, 2026. https://trim.imath.kiev.ua/index.php/trim/article/view/138.