Musienko, A. P., and A. S. Serdyuk. “Lebesgue-Type Inequalities for the De La Valee-Poussin Sums on Sets of Analytic Functions”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 4 (April 25, 2013): 522-537. Accessed April 19, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2436.