Karandeep Singh and  Baibing Li,  Traffic Density Estimation for Multiple Segment Freeways.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    June 2010, vol. 42(6). 655 - 659
    [viewed 22 January 2020]. Available from: https://publications.waset.org/pdf/1566.