WASET
    V.Rezaie and  M.Khanmohammady,  Ranking DMUs by Ideal PPS in Data Envelopment Analysis.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    July 2010, vol. 43(7). 565 - 570
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/12.