PIRZADA, S.; SAMEE, U.; NAIKOO, T.A.; MERAJUDDIN, S. Inequalities for marks in multidigraphs. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 28, p. 91–100, 2011. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/6009. Acesso em: 18 jul. 2026.