BabenkoV. F., and ChurilovaM. S. “Comparison of Exact Constants in Kolmogorov-Type Inequalities for Periodic and Nonperiodic Functions of Many Variables”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 58, no. 5, May 2006, pp. 597–606, https://umj.imath.kiev.ua/index.php/umj/article/view/3478.