GREEN, William L.; MORLEY, T. D. Operator means, fixed points, and the norm convergence of monotone approximants. Mathematica Scandinavica, Berkeley, CA, United States, v. 60, p. 202–218, 1987. DOI: 10.7146/math.scand.a-12180. Disponível em: https://journals.msp.org/mscand/article/view/1452. Acesso em: 25 jul. 2026.