1. V. S. Korolyuk and A. F. Turbin, Markov Renewal Processes in System Reliability Problems [in Russian], Naukova Dumka, Kiev (1982).
2. E. Arias and V. S. Korolyuk, “Stationary phase integration of Markov renewal processes,” Dop. AN Ukrainy, Ser. A, No. 8, 3–6 (1980).
3. A. M. Zubkov, “Sufficient conditions of the convergence of a sequence of random flows to an ordinary Poison flow,” in: Queuing Theory, Proc. 3rd All-Union Conference School on Queuing Theory [in Russian], Izd. Mosk. Gos. Univers., Vol. 1 (1976), pp. 197–202.
4. D. Szasz, “A problem of two lifts,” The Annals of Probability, 5, No.4, 550–559 (1977).
5. V. V. Kozlov, “The limiting theorem for a queuing system,” Teor. Veroyatn. Primen., 23, Issue 1, 190–195 (1978).