MASSOUROS, Ch.G.; TSITOURAS, Ch. Enumeration of hypercompositional structures defined by binary relations. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 28, p. 51–62, 2011. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/5993. Acesso em: 18 jul. 2026.