DRAGOMIR, S.S. Grüss’ type inequalities for functions of selfadjoint operators in Hilbert spaces. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 28, p. 205–222, 2011. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/5994. Acesso em: 18 jul. 2026.