Babenko, V. F., V. A. Kofanov, and S. A. Pichugov. “Comparison of Exact Constants in Inequalities for Derivatives of Functions Defined on the Real Axis and a Circle”. Ukrains’kyi Matematychnyi Zhurnal 55, no. 5 (May 25, 2003): 579–589. Accessed December 5, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/3934.