OPIELIŃSKI, Krzysztof J., et al. “A Digitally Controlled Model of an Active Ultrasonic Transducer Matrix for Projection Imaging of Biological Media”. Archives of Acoustics, vol. 35, no. 1, Nov. 2013, pp. 75-90, https://acoustics3.ippt.pan.pl/index.php/aa/article/view/258.