1. K. D�rschel et al., Z. Phys. A,312, 269 (1983).
2. G.D. Alkhazov et al., Z. Phys. A,316, 123 (1984).
3. E.Ye. Berlovich, Izv. AN SSSR, ser. phys.,29, 2177 (1965),43, 2046 (1979).
4. E.Ye. Berlovich et al., Proc. 8 th intern. EMIS Conference Sk�vde, Sweden, 349 (1973)
5. Izv. Akad. Nauk SSSR, ser.phys.,40, 2036 (1976).