BaevA. V., and BondarevB. V. 2006. “Invariance Principle for One Class of Markov Chains With Fast Poisson Time. Estimate for the Rate of Convergence”. Ukrains’kyi Matematychnyi Zhurnal 58 (9), 1155–1174. https://umj.imath.kiev.ua/index.php/umj/article/view/3520.