1. Golant V. E., Pilia A. D., Preprint No. 404 FTI AN SSSR Leningrad 1972 (to be published in Zh. Tekh. Fiz.).
2. Ďatlov J., Kryška L., Budnikov V. N., IPPCZ 169, Inst. Plasma Phys. Czechoslovak Acad. Sci., Prague 1972; Czech. J. Phys.B 23 (1973), 436.
3. Golant V. E., Pilia A. D., Uspekh. Fiz. Nauk104 (1971), 421.
4. Ďatlov J.,Kryška L., Paper presented to the 6. Czech. Seminar on Plasma Physics, Liblice 1972; see IPPCZ 167 (1972).
5. Vandenplas P. E., Electron Waves and Resonances in Bounded Plasmas. (John Wiley Inc. N. York 1968) and the references therein.