1. E. Nummelin, A Splitting Technique for φ-Recurrent Markov Chains, Inst. Math., Helsinki Univ. Technol. Espoo, Helsinki (1976).
2. A. A. Borovkov, “Ergodicity and stability theorems for a class of stochastic equations and their applications,” Teor. Veroyatn. Primenen., 23, Issue 2, 241–262 (1978).
3. K. B. Athreya and P. E. Ney, “A new approach to the limit theory of recurrent Markov chains,” Trans. Amer. Math. Soc., 245, No. 1, 493–501 (1978).
4. V. S. Korolyuk and A. F. Turbin, Markov Renewal Processes in System Reliability Problems [in Russian], Naukova Dumka, Kyiv (1982).
5. I. N. Kovalenko, “Limiting theorems of reliability theory,” Kibernetika, No. 6, 106–116 (1977).