TUKIA, P. On torsionless subgroups of infinitely generated Fuchsian groups. Annales Fennici Mathematici, [S. l.], v. 4, n. 2, p. 203–205, 1979. DOI: 10.5186/aasfm.1978-79.0428. Disponível em: https://afm.journal.fi/article/view/134348. Acesso em: 25 nov. 2024.