@INPROCEEDINGS {12306,
author={T. A. Morgado and S. Maslovski  and M. G. Silveirinha},
doi={},
booktitle={Metamorphose International Congress on Advanced Electromagnetic Materials in Microwaves and Optics - METAMATERIALS},
title={Negative Refraction by a Hyperbolic Metamaterial formed by Helical-Shaped Wires},
year={2012},
month={September},
volume={-},
pages={---} 
}