VakarchukS. B. “On the Best Approximation in the Mean and Overconvergence of a Sequence of Polynomials of the Best Approximation”. Ukrains’kyi Matematychnyi Zhurnal 52, no. 1 (January 25, 2000): 35-45. Accessed November 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4394.