Ambuj Kumar and  Sunil Kumar Singh and  Shrikant Singh,  Field Experience with Sweep Frequency Response Analysis for Power Transformer Diagnosis.   journal   = {International Journal of Energy and Power Engineering}, [online]. World Academy of Science, Engineering and Technology.
    October 2015, vol. 99(3). 392 - 399
    [viewed 18 October 2019]. Available from: https://publications.waset.org/pdf/10002913.