JIRIMUTU; XU, XIRONG; FENG, WEI; BAO, YULAN. Proof of a conjecture on the gracefulness of a digraph. Utilitas Mathematica , [S. l.], v. 81, 2010. Disponível em: https://utilitasmathematica.com/index.php/Index/article/view/724. Acesso em: 8 may. 2026.