On the rate of convergence of the sum of the squares of the $s$-values of the integral Hilbert - Schmidt’s operator. Neliniini Kolyvannya, [S. l.], v. 2, n. 3, p. 384–390, 1999. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/73. Acesso em: 22 jan. 2026.