SINGH, G.; KARUNAKARAN, K.; SINGH, J. Semigroup up of Graphs Over a Boolean Algebra. Journal of Qassim University for Science, [S. l.], v. 3, n. 1, p. 01–08, 2009. Disponível em: https://jnsm.qu.edu.sa/index.php/jnm/article/view/1740. Acesso em: 20 sep. 2024.