V. T. . Gavrilyuk, “On saturation classes of linear methods of the Fourier series summation ”, Ukr. Mat. Zhurn., vol. 40, no. 5, pp. 569–576, Aug. 1988, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8804