1. Piezoelectric torsional actuator;Fuda;Ferroelectrics,1994
2. Construction of megatorque hybrid transducer type ultrasonic motor;Satonobu;Jpn. J. Appl. Phys.,1996
3. E.L. Kyser, S.B. Sears, Method and apparatus for recording with writing fluids and drop projection means therefore, US Patent 3,946,398 (1976).
4. Ink-jet head with multi-layer piezoelectric actuator;Kitahara,1995
5. S.I. Zoltan, Pulse droplet ejection system, US Patent 3,683,212 (1974).