WASET
    Yasuhiko Okuma and  Yuichi Suzuki and  Takahiro Murakami and  Yoshihisa Ishida,  A Fast Directionally Constrained Minimization of Power Algorithm for Extracting a Speech Signal Perpendicular to a Microphone Array.   journal   = {International Journal of Electronics and Communication Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2007, vol. 1(1). 19 - 24
    [viewed 19 April 2024]. Available from: https://publications.waset.org/pdf/6228.