DIGERNES, T.; HUSSTAD, E.; VARADARAJAN, V. S. Finite approximation of Weyl systems. Mathematica Scandinavica, Berkeley, CA, United States, v. 84, n. 2, p. 261–283, 1999. DOI: 10.7146/math.scand.a-13879. Disponível em: https://journals.msp.org/mscand/article/view/949. Acesso em: 25 jul. 2026.