V. N. Konovalov, “Kolmogorov and linear widths of classes of s-monotone integrable functions”, Ukr. Mat. Zhurn., vol. 57, no. 12, pp. 1633–1652, Dec. 2005, Accessed: Apr. 23, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3715