BASU, C.K.; UZZAL AFSAN, B.M.; MANDAL, S.S. Degeneracy of some cluster sets. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 28, p. 63–78, 2011. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6014. Acesso em: 16 sep. 2026.