J. Lee, N. Nookala, M. Tymchenko, J.S. Gomez-Diaz, F. Demmerle, G. Boehm, K. Lai, G. Shvets, M.-C. Amann, A. Alu and M.A. Belkin.Gradient Nonlinear Metasurfaces for Continuous Phase Control.2016 Progress in Electromagnetics Research Symposium (PIERS).2016