1. A. V. Gaponov-Grekhov and M. I. Rabinovich, Izv. Vyssh. Uchebn. Zaved., Radiofiz.,30, 131 (1987).
2. K. Nozaki and N. Bekki, J. Phys. Soc. Jpn.,53, 1581 (1984).
3. E. Madelung, Z. Phys.,40, 322 (1926).
4. E. A. Spiegel, Physica,1D, 236 (1980).
5. A. I. Abakumov and B. V. Alekseev, Dokl. Akad. Nauk SSSR,262, 1100 (1982).