WAQAS, M.; AKBAR, Z.; ABID SAEED, M.; ALAM, S.; KHAN, M. J. Double Negative Metamaterial of Copper Split Ring and Graphite Materials. International Journal of Emerging Trends in Science and Technology, [S. l.], v. 1, n. 04, 2014. Disponível em: http://igmpublication.com/ijetst.in/index.php/ijetst/article/view/120. Acesso em: 31 jan. 2025.