W. T. A. Mohammed and  M. Eltaeb and  R. Kashani,  Passive and Active Spatial Pendulum Tuned Mass Damper with Two Tuning Frequencies.   journal   = {International Journal of Mechanical and Industrial Engineering}, [online]. World Academy of Science, Engineering and Technology.
    May 2024, vol. 209(5). 164 - 169
    [viewed 28 May 2024]. Available from: https://publications.waset.org/pdf/10013626.