[1]
A. S. Serdyuk, “Estimates of the Kolmogorov widths for classes of infinitely differentiable periodic functions”, Ukr. Mat. Zhurn., vol. 49, no. 12, pp. 1700–1706, Dec. 1997, Accessed: Feb. 17, 2026. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5176