Boonorm Chomtee and  John J. Borkowski,  Comparison of Response Surface Designs in a Spherical Region.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    May 2012, vol. 65(5). 545 - 548
    [viewed 20 April 2024]. Available from: https://publications.waset.org/pdf/11446.