HIRZALLAH, Omar; KITTANEH, Fuad. Numerical Radius Inequalities for Several Operators. Mathematica Scandinavica, Berkeley, CA, United States, v. 114, n. 1, p. 110–119, 2014. DOI: 10.7146/math.scand.a-16641. Disponível em: https://journals.msp.org/mscand/article/view/431. Acesso em: 24 jul. 2026.