Paulo Gomes and  Adelaide Figueiredo,  Clustering of Variables Based On a Probabilistic Approach Defined on the Hypersphere.   journal   = {International Journal of Mathematical and Computational Sciences}, [online]. World Academy of Science, Engineering and Technology.
    September 2013, vol. 82(10). 1535 - 1537
    [viewed 17 May 2021]. Available from: https://publications.waset.org/pdf/17113.