NOWICKI, A., W. SECOMSKI, P. KARŁOWICZ, and G. ŁYPACEWICZ. “High-Frequency Doppler Ultrasound Flowmeter”. Archives of Acoustics 19, no. 4 (December 31, 1994): 435–449. Accessed March 4, 2026. https://acoustics.ippt.gov.pl/index.php/aa/article/view/1110.