WASET
    D. Liu and  D. M. Donskoy,  Frequency Modulation in Vibro-Acoustic Modulation Method.   journal   = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2023, vol. 193(1). 42 - 47
    [viewed 23 April 2024]. Available from: https://publications.waset.org/pdf/10012906.