1. A. May, G. William, Piezoelectric electromechanical translation apparatus. United States Patent 3 902 084, 1975.
2. V. Vishnevsky, L. Gultiaeva, I. Kartaschew, V. Lavrinenko, Piezoelectric Motor. Russian Patent CCCP No. 851560, 1976–1981.
3. Characteristics of the Ultrasonic Linear Motor Using Radial and Nonaxisymmetric Vibration Modes of an Annular Plate
4. Ultrasonic Motors Theory and Applications;Ueha,1993
5. Transducer for high speed and large thrust ultrasonic linear motor using two sandwich-type vibrators;Kurosawa;IEEE Trans. Ultrasonics Ferroelec. Freq. Cont.,1998