1. . Finite Element Method for Piezoelectric Vibrations;Allik;International Journal for Numeric Methods in Engineering 2(2),1970
2. 2. Aoyagi, M.; Takano T.; Tamura, H.; Hirose, S. and Tomikawa, Y. 2008. Thin Ultrasonic Spindle-Motor Using Non-Axisymmetric ((1,1))-Mode of a Ring Vibrator. in Proceedings of Actuator 08 Conference, Bremen: 603-606
3. 3. ANSYS Release 10.0. 2009. Documentation for ANSYS. SAS IP, Inc.
4. 4. Bansevičius, R.; Giniotis, V. 2005. Mechatronic correctional devices for precision engineering, in Solid State Phenomena: Proc. of The 9-th International Conference Mechatronic Systems and Materials 2005, Vilnius, Lithuania, 429-434.
5. . Multi-degree-of-freedom ultrasonic motors for mass-consumer devices;Bansevičius;Journal of Electroceramics Dordrecht Springer 20(3-4) 221-,2008