k-out-of-n: G system with repair: the D-policy. - Achyutha Krishnamoorthy; P. V. Ushakumari (Comput. Oper. Res., 2001)

k-out-of-n system with repair: the max(N, T) policy. - P. V. Ushakumari; Achyutha Krishnamoorthy (Perform. Evaluation, 2004)

A retrial inventory system with an unreliable server. - P. V. Ushakumari (Int. J. Math. Oper. Res., 2017)

On a two-server reliability system with one-server idle below a threshold. - P. V. Ushakumari (Int. J. Math. Oper. Res., 2021)