LANDSTAD, Magnus B.; OLESEN, Dorte. Towards a Galois theory for crossed products of $C^*$-algebras. Mathematica Scandinavica, Berkeley, CA, United States, v. 43, p. 311–321, 1978. DOI: 10.7146/math.scand.a-11783. Disponível em: https://journals.msp.org/mscand/article/view/1867. Acesso em: 25 jul. 2026.