Rukasov VI, Chaichenko SO. Approximation of Analytic Periodic Functions by de la Vallée-Poussin Sums. Ukr. Mat. Zhurn. [Internet]. 2002Dec.25 [cited 2024Jul.27];54(12):1653-69. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/4204