Serdyuk, A.S. (2000) “Approximation of Periodic Functions of High Smoothness by Interpolation Trigonometric Polynomials in the Metric of $L_1$”, Ukrains’kyi Matematychnyi Zhurnal, 52(7), pp. 994–998. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4501 (Accessed: 10 April 2025).