S. Raja Balachandar and  K. Kannan,  A Meta-Heuristic Algorithm for Set Covering Problem Based on Gravity.   journal   = {International Journal of Physical and Mathematical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    July 2010, vol. 43(7). 1025 - 1030
    [viewed 18 April 2024]. Available from: https://publications.waset.org/pdf/16009.