WASET
    Milan Hladik,  A Contractor for the Symmetric Solution Set.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    November 2010, vol. 47(11). 1422 - 1427
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/7202.