José M. Merigó and  Montserrat Casanovas,  Geometric Operators in Decision Making with Minimization of Regret.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    March 2010, vol. 39(3). 369 - 376
    [viewed 23 January 2020]. Available from: https://publications.waset.org/pdf/11814.