1. V. A. Shchurov and A. V. Shchurov, Akust. Zh. 48, 110 (2002) [Acoust. Phys. 48, 98 (2002)].
2. M. D. Smaryshev and E. L. Shenderov, Akust. Zh. 31, 502 (1985) [Sov. Phys. Acoust. 31, 296 (1985)].
3. A. V. Pesotskii and M. D. Smaryshev, Akust. Zh. 35, 495 (1989) [Sov. Phys. Acoust. 35, 289 (1989)].
4. E. L. Shenderov, in Hydroacoustics (St. Petersburg, 2002), No. 3, p. 24 [in Russian].