MAURER, H. A.; SALOMAA, A.; WELZL, E.; WOOD, D. Denseness, maximality, and decidability of grammatical families. Annales Fennici Mathematici, [S. l.], v. 11, n. 2, p. 167–178, 1986. DOI: 10.5186/aasfm.1986.1114. Disponível em: https://afm.journal.fi/article/view/134569. Acesso em: 25 nov. 2024.