Serdyuk AS. Approximation of Infinitely Differentiable Periodic Functions by Interpolation Trigonometric Polynomials in Integral Metric. Ukr. Mat. Zhurn. [Internet]. 2001 Dec. 25 [cited 2025 Dec. 6];53(12):1654-63. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/4385