RomanyukA. S. and RomanyukV. S. (2013) “Best Bilinear Approximations for the Classes of Functions of Many Variables”, Ukrains’kyi Matematychnyi Zhurnal, 65(12), pp. 1681–1699. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2546 (Accessed: 24November2024).