A two-unit system with correlated failures and repairs, and random appearance and disappearance of repairman. - Rakesh Gupta; P. K. Tyagi; Ram Kishan (Int. J. Syst. Sci., 1996)

On the profit comparison of two stochastic models each pertaining to a two-unit standby system with fixed preparation time and hyperexponential repair time distributions. - Rakesh Gupta; Ram Kishan (Int. J. Syst. Sci., 1999)

A two-non-identical-unit parallel system with correlated lifetimes. - Rakesh Gupta; Ram Kishan; Pawan Kumar (Int. J. Syst. Sci., 1999)

Classical and Bayesian analysis of reliability characteristics of a two-unit parallel system with Weibull failure and repair laws. - Ram Kishan; Divya Jain (Int. J. Syst. Assur. Eng. Manag., 2014)