Hailong Zhu and  Zhaoxiang Li,  A Numerical Algorithm for Positive Solutions of Concave and Convex Elliptic Equation on R2.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    July 2010, vol. 43(7). 870 - 873
    [viewed 24 April 2024]. Available from: https://publications.waset.org/pdf/10097.