Application of laser-produced extended plasma plumes for generation and characterization of the high-order harmonics of 64 fs pulsesRashid A. Ganeev, Masayuki Suzuki and Hiroto KurodaEur. Phys. J. D, 68 11 (2014) 332DOI: https://doi.org/10.1140/epjd/e2014-50175-6