1. W.M. Mullins, R.D. Irwin, S. Venugopal, and J.C. Malas, “Examination on the Use of Acoustic Emission for Monitoring Metal Forging Processes,” submitted to Scripta Materilia, 1996
2. W. Anderson, Controlling Electrohydraulic Systems, Marcel Dekker, 1988
3. E.E. Lewis and H. Stern, Design of Hydraulic Control Systems, McGraw-Hill, 1962
4. P.M. DeRusso, R.J. Roy, and C.M. Close, State-Variables for Engineers, John Wiley & Sons, 1965
5. J.G. Truxal, Control System Synthesis, McGraw-Hill, 1955