WASET
    Osama Terra and  Hatem Hussein and  Adriaan Van Brakel,  Bi-Lateral Comparison between NIS-Egypt and NMISA-South Africa for the Calibration of an Optical Spectrum Analyzer.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    October 2017, vol. 132(12). 507 - 511
    [viewed 25 April 2024]. Available from: https://publications.waset.org/pdf/10008284.