Mamoun F. Al-Mistarihi,  Quadratic Pulse Inversion Ultrasonic Imaging(QPI): A Two-Step Procedure for Optimization of Contrast Sensitivity and Specificity.   journal   = {International Journal of Electronics and Communication Engineering}, [online]. World Academy of Science, Engineering and Technology.
    April 2010, vol. 40(4). 727 - 732
    [viewed 14 October 2019]. Available from: https://publications.waset.org/pdf/2581.