HAAGERUP, U.; KADISON, R. V.; PEDERSEN, G. K. Means of unitary operators, revisited. MATHEMATICA SCANDINAVICA, [S. l.], v. 100, n. 2, p. 193–197, 2007. DOI: 10.7146/math.scand.a-15021. Disponível em: https://www.mscand.dk/article/view/15021. Acesso em: 27 apr. 2024.