GURRAM, Dharmaiah. {2, 2}-EXTENDABILITY OF PLANAR GRAPHS. Journal of Global Research in Mathematical Archives(JGRMA), [S. l.], v. 1, n. 3, p. 54–59, 2013. Disponível em: https://www.jgrma.com/index.php/jgrma/article/view/42. Acesso em: 10 may. 2025.