Bodenchuk, V. V., and A. S. Serdyuk. 2015. “Exact Values of Kolmogorov Widths for the Classes of Analytic Functions. II”. Ukrains’kyi Matematychnyi Zhurnal 67 (8), 1011-18. https://umj.imath.kiev.ua/index.php/umj/article/view/2041.