Agrafiotis, G.K., P.R. Parthasarathy and M. Sharafali, “Excess repair time for repairable system”, Microelectronic, Reliability., 30(3), 507-509, (1990).
Arora, J.R., “Reliability of a two-unit priority standby redundant system with finite repair capability” IEEE Trans., Reliability, R-25, 205-207, (1976).
Billinton. R., and Jun Pan, “Optimal maintenance scheduling in a two identical component parallel redundant system”, Reliability, Engineering. & System Safety, 39(3), 309-316, (March 1998).