Parvinder S. Sandhu and  Urvashi Malhotra and  E. Ardil,  Predicting the Impact of the Defect on the Overall Environment in Function Based Systems.   journal   = {International Journal of Computer and Systems Engineering}, [online]. World Academy of Science, Engineering and Technology.
    August 2009, vol. 32(8). 1923 - 1926
    [viewed 21 January 2020]. Available from: https://publications.waset.org/pdf/7950.