NG, Kung-fu. On a Theorem of Dixmier. MATHEMATICA SCANDINAVICA, [S. l.], v. 29, p. 279–280, 1971. DOI: 10.7146/math.scand.a-11054. Disponível em: https://tidsskrift.dk/math/article/view/11054. Acesso em: 14 aug. 2026.