WILS, Wilbert. Direct Integrals of Hilbert Spaces I. Mathematica Scandinavica, Berkeley, CA, United States, v. 26, p. 73–88, 1970. DOI: 10.7146/math.scand.a-10967. Disponível em: https://journals.msp.org/mscand/article/view/2360. Acesso em: 25 jul. 2026.