MUHLY, Paul S.; WILLIAMS, Dana P. Continous trace groupoid $C^*$-algebras. Mathematica Scandinavica, Berkeley, CA, United States, v. 66, p. 231–241, 1990. DOI: 10.7146/math.scand.a-12307. Disponível em: https://journals.msp.org/mscand/article/view/1317. Acesso em: 24 jul. 2026.