SolodkiiS. G. “On Information Complexity of Certain Classes of Operator Equations”. Ukrains’kyi Matematychnyi Zhurnal 49, no. 9 (September 25, 1997): 1271–1277. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5126.