1. V. G. Romanov, Stability in Inverse Problems (Nauchn. Mir, Moscow, 2005) [in Russian].
2. S. I. Kabanikhin, Inverse and Ill-Posed Problems (Sibirsk. Nauchn. Izd., Novosibirsk, 2009) [in Russian].
3. A. L. Goryunov and A. V. Saskovets, Inverse Scattering Problems in Acoustics (MGU, Moscow, 1989) [in Russian].
4. N. V. Alekseenko, V. A. Burov, and O. D. Rumyantseva, Akust. Zh. 54 (3), 469 (2008).
5. V. A. Burov, S. N. Vecherin, S. A. Morozov, and O. D. Rumyantseva, Akust. Zh. 56 (4), 516 (2010).