Islam, M Ataharul, Rafiqul I. Chowdhury, and Karan P. Singh. “A Markov Model for Analyzing Polytomous Outcome Data”. Pakistan Journal of Statistics and Operation Research 8, no. 3 (July 1, 2012): 593-603. Accessed July 26, 2025. https://pjsor.com/pjsor/article/view/530.