R. C. CHIVERS, “Quantitative image indices in ultrasonic diagnostics of inbomogeneous materials”, Arch. Acoust., vol. 6, no. 2, pp. 147–162, Jun. 1981, Accessed: Mar. 04, 2026. [Online]. Available: https://acoustics.ippt.gov.pl/index.php/aa/article/view/3303