PRAISACH, Zeno-Iosif, et al. “Dimensionless Wave Numbers Evolution of a Three Spans Simply Supported Beam When the Intermediate Supports Are Moving Along the Whole Beam”. Studia Universitatis Babeș-Bolyai Engineering, vol. 66, no. 1, Nov. 2021, pp. 17-24, doi:10.24193/subbeng.2021.1.2.