Processing Times for Transaction Servers with Quality of Service Differentiation. - Hans van den Berg; Robert D. van der Mei; Bart Gijsen; Martin Pikaart; Ralf Vranken (MMB, 2001)

Sojourn-time approximations for a multi-server processor sharing system with priorities. - Robert D. van der Mei; J. L. van den Berg; Ralf Vranken; Bart Gijsen (Perform. Evaluation, 2003)