IsakovaT. I., and FilonovY. P. “Integral Conditions for the Invertibility of Markov Chains on a Half-Line With General Measure of Irreducibility”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 56, no. 5, May 2004, pp. 705-12, https://umj.imath.kiev.ua/index.php/umj/article/view/3791.