WASET
    Priyadarsini P. L. K and  Hemalatha T.,  Connected Vertex Cover in 2-Connected Planar Graph with Maximum Degree 4 is NP-complete.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    November 2007, vol. 11(11). 570 - 573
    [viewed 18 April 2024]. Available from: https://publications.waset.org/pdf/13006.