Un-Hwan Park and  Jun-Hyeok Heo and  In-Sung Lee and  Tae-Hyeon Oh and  Dae-Kyu Park,  The Design Optimization for Sound Absorption Material of Multi-Layer Structure.   journal   = {International Journal of Aerospace and Mechanical Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2018, vol. 133(1). 41 - 44
    [viewed 11 May 2024]. Available from: https://publications.waset.org/pdf/10008526.