S. Balaji and  V. Swaminathan and  K. Kannan,  Optimization of Unweighted Minimum Vertex Cover.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    July 2010, vol. 43(7). 941 - 946
    [viewed 10 May 2021]. Available from: https://publications.waset.org/pdf/12686.