Hunstig, Matthias, Tobias Hemsel, and Walter Sextro. “An Efficient Simulation Technique for High-Frequency Piezoelectric Inertia Motors.”https://doi.org/10.1109/ULTSYM.2012.0068__In Ultrasonics Symposium (IUS), 2012 IEEE International, 277–80, 2012.https://doi.org/10.1109/ULTSYM.2012.0068 .