Erna T. Herdiani and  Maman A. Djauhari,  Distribution Sampling of Vector Variance without Duplications.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    December 2012, vol. 72(12). 1673 - 1676
    [viewed 23 May 2022]. Available from: https://publications.waset.org/pdf/2465.