SOLICH, K. V. Best bilinear approximations of the classes $S^{\Omega}_{p, \theta}B$ of periodic functions of many variables. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 63, n. 6, p. 809–826, 2011. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2764. Acesso em: 5 dec. 2025.