VakarchukS. B. “The Best Polynomial Approximation of Functions Analytical in the Single Circle ”. Ukrains’kyi Matematychnyi Zhurnal 42, no. 6 (June 19, 1990): 838-843. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/8849.