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2. N.A. Vinokurov, A.N. Skrinskii: ?Limiting power of an optical klystron on a linear electron accelerator?, preprint INP 78-88, Novossibirsk (1978)
3. See also: I. Boscolo, V. Stagno: Nuovo Cimento58B, 267 (1980)
4. C. Brautti et al.: Boll. Soc. Ital. Fis.112, 67 (1977)
5. D.F. Alferov, E.G. Bessonov: Sov. Phys. Tech. Phys.24, 450?455 (1979)