AMERI, R.; BORZOOEI, R.A.; GHADIMI, K. REPRESENTATIONS OF POLYGROUPS. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 37, p. 595–610, 2017. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6673. Acesso em: 16 sep. 2026.