VakarchukS. B., and ShvachkoA. V. “On the Best Approximation in the Mean by Algebraic Polynomials With Weight and the Exact Values of Widths for the Classes of Functions”. Ukrains’kyi Matematychnyi Zhurnal 65, no. 12 (December 25, 2013): 1604–1621. Accessed November 21, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2540.