E. O. Polulyakh and I. Y. Vlasenko, “On iteration stability of the Birkhoff center with respect to power 2”, Ukr. Mat. Zhurn., vol. 58, no. 5, pp. 705–707, May 2006, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3487