Non-rotationally invariant invisibility cloaks and concentrators of EM WavesG. X. Yu, W. X. Jiang, X. Y. Zhou and T. J. CuiEur. Phys. J. Appl. Phys., 44 2 (2008) 181-185DOI: https://doi.org/10.1051/epjap:2008152