ZHAO, LINGQI; FENG, WEI; JIRIMUTU. On the gracefulness of the digraphs n - C→m. Utilitas Mathematica , [S. l.], v. 82, 2010. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/705. Acesso em: 8 may. 2026.