The paper describes the reliability of working-order of a serial arrangement of blocks with laid-off reserves and a certain regime of repairs. This model is then applied to the situation of an automatic computing device.
 Birnbaum, Esary, Saunders: Multicomponent Systems and Structures and Their Reliability
. Technometrics 3 (1961). MR 0122658
 Bharucha, Reid: Elements of the Theory of Markov Processes and Their Applications
. 1960. Zbl 0181.44702