Piezoelectric transformers - state of the art and development trends
T. Hemsel, W. Littmann, J. Wallaschek, in: Ultrasonics Symposium, 2002. Proceedings. 2002 IEEE, 2002, pp. 645–648.
LibreCat: /record/8926
DOI: 10.1109/ULTSYM.2002.1193485

State of the art and development trends of ultrasonic linear motors
T. Hemsel, J. Wallaschek, in: Ultrasonics Symposium, 2000 IEEE, 2000, pp. 663–666 vol.1.
LibreCat: /record/8915
DOI: 10.1109/ULTSYM.2000.922635