Babenko, V. F., M. S. Gun’ko, and A. A. Rudenko. “Optimal Recovery of <em class="a-Plus-plus">n</Em&gt;-Linear Functionals According to Linear Information”. Ukrains’kyi Matematychnyi Zhurnal 66, no. 7 (July 25, 2014): 884–890. Accessed April 25, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/2186.