Tulika Bhattacharjee and  A. K.Chakraborty,  DEMO Based Optimal Power Purchase Planning Under Electricity Price Uncertainty.   journal   = {International Journal of Energy and Power Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2012, vol. 61(1). 101 - 106
    [viewed 22 February 2020]. Available from: https://publications.waset.org/pdf/913.