Kristjan Kuhi and  Kati K. Kaare and  Ott Koppel,  Estimation of Missing or Incomplete Data in Road Performance Measurement Systems.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2013, vol. 82(10). 1904 - 1910
    [viewed 22 October 2021]. Available from: https://publications.waset.org/pdf/16935.