Bodenchuk, V. V., & Serdyuk, A. S. (2015). Exact Values of Kolmogorov Widths for the Classes of Analytic Functions. I. Ukrains’kyi Matematychnyi Zhurnal, 67(6), 719-738. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/2017