Koschny T, Zhou J, Soukoulis CM. Magnetic response and negative refractive index of metamaterials - art. no. 658103. In: Kuzmiak V, Markos P, editors. Metamaterials II. Vol 6581. Bellingham: Spie-Int Soc Optical Engineering; 2007. p. 58103. (Proceedings of the Society of Photo-Optical Instrumentation Engineers (Spie); vol 6581). Abstract