[1]
A. K. Kushpel, “On the Lebesgue constants”, Ukr. Mat. Zhurn., vol. 71, no. 8, pp. 1073–1081, Aug. 2019, Accessed: Feb. 16, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/1499