V. F. Babenko, M. S. Gun’ko, and A. A. Rudenko, “Optimal Recovery of n-Linear Functionals According to Linear Information”, Ukr. Mat. Zhurn., vol. 66, no. 7, pp. 884–890, Jul. 2014, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2186