Propagation of optical beams in two transverse gradient index media A. Martín-Ruiz, J. Martín-Heredia, L. A. Ruiz-Ochoa and E. Chan-López Eur. Phys. J. D, 70 5 (2016) 110 Published online: 12 May 2016 DOI: 10.1140/epjd/e2016-60645-4