AUGUSTYN, Elżbieta, et al. “FEM Analysis of Active Reduction of Torsional Vibrations of Clamped-Free Beam by Piezoelectric Elements for Separated Modes”.
Archives of Acoustics, vol. 39, no. 4, Dec. 2014, pp. 639-44,
https://doi.org/10.2478/aoa-2014-0069.