Phengsalae, Y., Y. Areepong, and S. Sukparungsee. “An Approximation of ARL for Poisson GWMA Using Markov Chain Approach”. Thailand Statistician, vol. 13, no. 1, May 2015, pp. 111-24, https://ph02.tci-thaijo.org/index.php/thaistat/article/view/34189.