RAO, D. R. S. Alphabets, Numbers, Punctuation profess Micro Graph Theory. International Journal of Emerging Trends in Science and Technology, [S. l.], v. 2, n. 07, 2015. Disponível em: http://igmpublication.com/ijetst.in/index.php/ijetst/article/view/799. Acesso em: 31 jan. 2025.