Pham Thi Quynh and  Huynh Quyet Thang,  Dynamic Coupling Metrics for Service – Oriented Software.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    March 2009, vol. 27(3). 795 - 800
    [viewed 21 October 2019]. Available from: https://publications.waset.org/pdf/2975.