“EM ALGORITHM FOR MAXIMUM LIKELIHOOD ESTIMATION OF CORRELATED PROBIT MODEL FOR TWO LONGITUDINAL ORDINAL OUTCOMES”, Ann. Sofia Univ. Fac. Math. and Inf., vol. 104, pp. 217–232, Dec. 2017, Accessed: Feb. 04, 2026. [Online]. Available: https://annual.uni-sofia.bg/index.php/fmi/article/view/47