Klimonda, Ziemowit, and Andrzej Nowicki. “Imaging of the Mean Frequency of the Ultrasonic Echoes”. Archives of Acoustics 32, no. 4(S) (January 1, 2014): 77–80. Accessed August 15, 2025. https://acoustics.ippt.pan.pl/index.php/aa/article/view/1392.