Yan Shuang Zhang and  Taehan Lee and  Byung Ho Jeong,  A Dual Model for Efficiency Evaluation Considering Time Lag Effect.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2013, vol. 79(7). 1579 - 1582
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/16498.