Parekhan M. Jaff,  Characteristic of Discrete Raman Amplifier at Different Pump Configurations.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2009, vol. 30(6). 424 - 426
    [viewed 25 January 2020]. Available from: https://publications.waset.org/pdf/8526.