Z. Noranai and  M.Z. Md Yusof,  Economical Analysis of Thermal Energy Storage by Partially Operation.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    November 2011, vol. 59(11). 2383 - 2387
    [viewed 21 October 2019]. Available from: https://publications.waset.org/pdf/9922.