VESTERSTROM, J.; WILS, W. Direct Integrals of Hilbert Spaces II. MATHEMATICA SCANDINAVICA, [S. l.], v. 26, p. 89–102, 1970. DOI: 10.7146/math.scand.a-10968. Disponível em: https://www.mscand.dk/article/view/10968. Acesso em: 28 apr. 2024.