Issue No. 04 - April (1980 vol. 13)
J.P. Buzen , BGS Systems, Inc.
Operational analysis, an alternative to stochastic analysis based on measurable variables rather than abstract parameters, simplifies proofs of formulas for computing response times and queue lengths.
J.P. Buzen, P.J. Denning, "Measuring and Calculating Queue Length Distributions", Computer, vol. 13, no. , pp. 33-44, April 1980, doi:10.1109/MC.1980.1653574