Manoj Kumar and  Rajesh Kumar,  Perspectives of Renewable Energy in 21st Century in India: Statistics and Estimation.   journal   = {International Journal of Energy and Power Engineering}, [online]. World Academy of Science, Engineering and Technology.
    June 2017, vol. 126(6). 747 - 755
    [viewed 16 October 2019]. Available from: https://publications.waset.org/pdf/10007695.