D. PAUL DHAYABARAN, P. S. SKOLEM GRACEFUL SIGNED GRAPHS ON DIRECTED GRAPHS. Asian Journal of Current Engineering and Maths, [S. l.], v. 3, n. 3, 2014. Disponível em: https://innovativejournal.in/index.php/ajcem/article/view/796. Acesso em: 22 jul. 2024.