Zhang , Gang-TaiBai , Ting-Ting and Zhang , Mei-Guang. (2013). Isolated Sub-50 Attosecond Pulse Generation in the Combined Mid-Infrared Laser Field.
            <i>Journal of Atomic and Molecular Sciences</i>. <i>4</i> (3).
            251-260.
         doi:10.4208/jams.070112.073012a