High-order harmonic generation at high laser intensities beyond the tunnel regimeJose Antonio Pérez-Hernández, Marcelo F. Ciappina, Maciej Lewenstein, Amelle Zaïr and Luis RosoEur. Phys. J. D, 68 7 (2014) 195DOI: https://doi.org/10.1140/epjd/e2014-50086-6