NGUYEN, K. Classification criteria for regular trees. Annales Fennici Mathematici, [S. l.], v. 47, n. 1, p. 3–21, 2021. DOI: 10.54330/afm.112449. Disponível em: https://afm.journal.fi/article/view/112449. Acesso em: 7 apr. 2025.