1. V. E. Borodin et al., Preprint IHEP 74-131, Serpukhov (1974).
2. M. Höfert, Preprint CERN DI/HP/187, Geneva (1975).
3. M. Höfert, Preprint CERN DI/HP/177, Geneva (1974).
4. V. T. Golovachik et al., in: Proceedings of the International Congress on Protection against Accelerator and Space Radiation, CERN, Geneva, Apr. 26?30, 1971. CERN 71-16, Vol. 1, p. 431.
5. I. S. Baishev et al., in: Proceedings of the Fifth All-Union Conference on Charged Particle Accelerators [in Russian], Vol. 1, Nauka, Moscow (1977), p. 224; Preprint CERN HS-RP/104, Geneva (1977).