Vakarchuk, S. B. “Jackson-Type Inequalities for the Special Moduli of Continuity on the Entire Real Axis and the Exact Values of Mean $ν$ - Widths for the Classes of Functions in the Space $L_2 (ℝ)$”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 6 (June 25, 2014): 740–766. Accessed March 29, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2175.