Hyun-Woo Cho,  Empirical Process Monitoring Via Chemometric Analysis of Partially Unbalanced Data .   journal   = {International Journal of Industrial and Manufacturing Engineering}, [online]. World Academy of Science, Engineering and Technology.
    October 2013, vol. 83(11). 2231 - 2235
    [viewed 23 April 2021]. Available from: https://publications.waset.org/pdf/17386.