MacDougald, D. J., P. C. Hines, and J. C. Osler. “The Effects of Azimuthal Variability on Monostatic Acoustic Backscatter from the Seabed”. Canadian Acoustics, vol. 30, no. 3, Sept. 2002, pp. 98-99, https://jcaa.caa-aca.ca/index.php/jcaa/article/view/1473.