Romanyuk AS, Romanyuk VS. Estimates for the best bilinear approximations of the classes $B^r_{p,\theta}$ and singular numbers of integral operators. Ukr. Mat. Zhurn. [Internet]. 2016Sep.25 [cited 2024Nov.21];68(9):1240-5. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/1917