KonovalovV. N. “Kolmogorov and Linear Widths of Classes of S-Monotone Integrable Functions”. Ukrains’kyi Matematychnyi Zhurnal 57, no. 12 (December 25, 2005): 1633–1652. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3715.