Romanyuk, A.S. and Romanyuk, V.S. (2016) “Estimates for the best bilinear approximations of the classes $B^r_{p,\theta}$ and singular numbers of integral operators”, Ukrains’kyi Matematychnyi Zhurnal, 68(9), pp. 1240–1250. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/1917 (Accessed: 10 April 2025).