Randy Gomez and  Keisuke Nakamura and  Kazuhiro Nakadai,  Automatic Distance Compensation for Robust Voice-based Human-Computer Interaction.   journal   = {International Journal of Computer and Information Engineering}, [online]. World Academy of Science, Engineering and Technology.
    July 2013, vol. 79(7). 974 - 983
    [viewed 28 February 2020]. Available from: https://publications.waset.org/pdf/16406.