WASET
    Khin Fai Chen and  Jee-Hou Ho and  Eng Hwa Yap,  Piezoelectric Approach on Harvesting Acoustic Energy.   journal   = {International Journal of Energy and Power Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2015, vol. 104(8). 774 - 780
    [viewed 28 March 2024]. Available from: https://publications.waset.org/pdf/10001948.