WASET
    Sepulveda Juan,  Renewable Energy Trends Analysis: A Patents Study.   journal   = {International Journal of Energy and Power Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2016, vol. 110(2). 243 - 247
    [viewed 26 April 2024]. Available from: https://publications.waset.org/pdf/10003637.