1. V. A. Grigor'ev, Vestn. Akad. Nauk SSSR, No. 4, 84?90 (1987).
2. A. D. Timokhin, Tr. Mosk. énerg. Inst., No. 545, 3?24 (1981).
3. J. Rayleigh, Theory of Sound [Russian translation], Vol. 2, Moscow (1955).
4. J. M. Schneider and C. D. Hendricks, Rev. Sci. Instrum.,35, No. 10, 1349?1350 (1964).
5. USA Patent No. 3,512,173, NKI 346-75.