SECOMSKI, W., NOWICKI, A., WÓJCIK, J., LEWANDOWSKI, M., WALCZAK, M., & TYMKIEWICZ, R. (2013). Annular Array Transducer and Matched Amplifier for Therapeutic Ultrasound. Archives of Acoustics, 35(4), 653–660. https://acoustics3.ippt.pan.pl/index.php/aa/article/view/220