T. WASZCZUK, T. KUJAWSKA, and J. C. SOMER, “Electronic focusing of the ultrasonic beam by means of an annular array system”, Arch. Acoust., vol. 9, no. 1-2, pp. 155–162, Jul. 2015, Accessed: Jun. 15, 2025. [Online]. Available: https://acoustics.ippt.pan.pl/index.php/aa/article/view/3208