1. A. Ellman & T. Virvalo, Formation of pressure gain in hydraulic servovalves and its significance in system behaviour, Proc. ASME Fluid Power Systems and Technology Division, Atlanta, 1996, 77–81.
2. A. Ellman, Leakage behaviour of four-way servovalve, Proc. ASME Fluid Power Systems and Technology Division, Anaheim, CA, 1998, 163–167.
3. M. Feki, E. Richard, & F. Gomes Almeida, Commande en effort d’un vérin hydraulique par linéarization entrée/sortie, Journées Doctorales d’Automatiques, JDA’99, Nancy, France, 1999, 181–184.
4. H.E. Merritt, Hydraulic control systems (USA: John Wiley & Sons, 1967).
5. W.J. Thayer, Specification standards for electrohydraulic flow control servovalves, Technical Bulletin 117, MOOG Inc. Control Division, New York, 1962.