Before revision:  This paper further broadens this family by introducing pass-and-swap (P&S) queues, an extension of OI queues where any customer that completes service is not necessarily the customer that leaves the system.
After revision:  This paper further broadens this family by introducing pass-and-swap (P&S) queues, an extension of OI queues where , upon a service completion, the customer that completes service is not necessarily the customer that leaves the system.