Adil Salam and  Nadia Bhuiyan and  Gerard J. Gouw,  Parametric Cost Estimating Relationships for Design Effort Estimation.   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2013, vol. 79(7). 1359 - 1364
    [viewed 30 September 2020]. Available from: https://publications.waset.org/pdf/16365.