Syed Javed Arif and  Mohd Ayyub Khan and  Saleem Anwar Khan,  Digital Encoder Based Power Frequency Deviation Measurement .   journal   = {International Journal of Electronics and Communication Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2019, vol. 151(7). 472 - 476
    [viewed 20 November 2019]. Available from: https://publications.waset.org/pdf/10010565.