M. Zahedian and  B. Maraghechi and  M. H. Rouhani,  Nonlinear Simulation of Harmonically Coupled Two-Beam Free-Electron Laser.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2011, vol. 54(6). 895 - 898
    [viewed 18 April 2024]. Available from: https://publications.waset.org/pdf/14585.