Saman Ghaffarian and  Ilgın Gökasar,  Traffic Density Measurement by Automatic Detection of Vehicles Using Gradient Vectors from Aerial Images.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2015, vol. 104(8). 973 - 977
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/10001868.