Brock, Jeffrey B., Andrew A. Houck, and Isaac L. Chuang. 2004. “Focusing Inside Negative Index Materials”. Applied Physics Letters. Reference Link
Houck, Andrew A., Jeffrey B. Brock, and Isaac L. Chuang. 2003. “Experimental Observations of a Left-Handed Material That Obeys Snell’s Law”. Physics Review Letters. Referenced from journals.aps.org: Experimental Observations of a Left-Handed Material That Obeys Snell’s Law. Reference Link