LARSEN, N. S.; RAEBURN, Iain. Faithful representations of crossed products by actions of $\boldsymbol N^k$. Mathematica Scandinavica, Berkeley, CA, United States, v. 89, n. 2, p. 283–296, 2001. DOI: 10.7146/math.scand.a-14342. Disponível em: https://journals.msp.org/mscand/article/view/863. Acesso em: 24 jul. 2026.