1. Belinsky, V. A., and Zakharov, V. E. (1978).Sov. Phys. JETP,48, 985.
2. Belinsky, V. A., and Zakharov, V. E. (1980).Sov. Phys. JETP,50, 1.
3. Alekseev, A., and Belinsky, V. A. (1980).Sov. Phys. JETP,51, 655.
4. Jantzen, R. T. (1980).Nuovoe Cimento,59B, 287.
5. Bondi, H. (1957).Rev. Mod. Phys.,29, 423.