AUGUSTHY, Germina K.; SOORYA, P. Vertex (n, k)-choosability of graphs. Italian Journal of Pure and Applied Mathematics, [S. l.], v. 43, p. 905–911, 2020. Disponível em: https://journals.uniurb.it/index.php/ijpam/article/view/7277. Acesso em: 28 oct. 2026.