4[2]Water hydraulics. A technical data book. BFPA/P82
5[3]Striker S. Advances make tap water hydraulics more practical. Hydraulics & Pneumatics,1996:29~32
6[4]E. Trostmann, P. M. Clausen. Hydraulic components using water as pressure medium. Proc. 4th Scandinavian Int. Conf. On Fluid Power. Tampere, Finland, Sept. 1995:942~954