[1]
L. FILIPCZYŃSKI and J. SAŁKOWSKI, “Attempts at the ultrasonic visualization of the heart in real time”, Arch. Acoust., vol. 2, no. 3, pp. 225–230, Sep. 1977, Accessed: Apr. 18, 2026. [Online]. Available: http://acoustics.ippt.gov.pl/index.php/aa/article/view/3486