Branislav Timotijevic and  Yves Petremand and  Markus Luetzelschwab and  Dara Bayat and  Laurent Aebi,  Compact Optical Sensors for Harsh Environments.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2017, vol. 128(8). 369 - 374
    [viewed 18 April 2021]. Available from: https://publications.waset.org/pdf/10007697.