A. Hadi-Vencheh and  N. Shayesteh Moghadam,  A Hybrid DEA Model for the Measurement of the Enviromental Performance.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    March 2011, vol. 51(3). 424 - 428
    [viewed 27 January 2021]. Available from: https://publications.waset.org/pdf/7083.