Said Rabah Azzam and  Laura Carolina Arias and  Shikun Zhou,  Managing a Manufacturing System with Integration of Walking Worker and Lean Thinking.   journal   = {International Journal of Economics and Management Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2011, vol. 55(7). 925 - 927
    [viewed 26 January 2020]. Available from: https://publications.waset.org/pdf/9699.