Pandit, Parameshwar V, and Savitha Kumari. “A CLASS OF DISTRIBUTION-FREE TESTS FOR INDEPENDENCE AGAINST POSITIVE QUADRANT DEPENDENCE”. Pakistan Journal of Statistics and Operation Research 9, no. 4 (February 6, 2014): 373-379. Accessed September 24, 2021. https://pjsor.com/pjsor/article/view/611.