Marco Ajmone Marsan Susanna Donatelli U. Rubino Fabio Neri GSPN Models of Random, Cyclic, and Optimal 1-Limited Multiserver Multiqueue Systems. 69-80 1991 SIGCOMM http://doi.acm.org/10.1145/115992.116000 db/conf/sigcomm/sigcomm1991.html#MarsanDRN91