PATERSON, Alan L. T. Contractive Spectral Triples for Crossed Products. Mathematica Scandinavica, Berkeley, CA, United States, v. 114, n. 2, p. 275–298, 2014. DOI: 10.7146/math.scand.a-17112. Disponível em: https://journals.msp.org/mscand/article/view/420. Acesso em: 24 jul. 2026.