CERONE, P.; DRAGOMIR, S. S. A refinement of the Gr"{u}ss inequality and applications. Tamkang Journal of Mathematics, [S. l.], v. 38, n. 1, p. 37-49, 2007. DOI: 10.5556/j.tkjm.38.2007.92. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/92. Acesso em: 10 apr. 2021.