1. L. Bergmann, Ultrasonics (Bell, London, 1938; Inostrannaya Literatura, Moscow, 1956).
2. Ultrasound. Small Encyclopedia (Sovetskaya Entsiklopediya, Moscow, 1979) [in Russian].
3. J. W. Tucker and V. W. Rampton, Microwave Ultrasonics in Solid State Physics (North Holland, Amsterdam, 1972; Mir, Moscow, 1975).
4. S. S. Karinskii, Processing Devices of Signals on Ultrasonic Ground Waves (Sovetskoe Radio, Moscow, 1975) [in Russian].
5. Yu. V. Gulyaev, Problems of Modern Radio Engineering and Electronics, Ed. by V. A. Kotel’nikov (Nauka, Moscow, 1980) [in Russian].