Myleiko, G. L., and S. G. Solodkii. “Hyperbolic Cross and Complexity of Various Classes of Linear Ill-Posed Problems”. Ukrains’kyi Matematychnyi Zhurnal 69, no. 7 (July 25, 2017): 951–963. Accessed April 7, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/1748.