SALOMAA, A. On meta-normal forms for algebraic power series in noncommuting variables. Annales Fennici Mathematici, [S. l.], v. 10, n. 1, p. 501–510, 1985. DOI: 10.5186/aasfm.1985.1056. Disponível em: https://afm.journal.fi/article/view/134551. Acesso em: 25 nov. 2024.