1. Faddeev, L. D. and Buslaev, V. S., Dokl. Akad. Nauk SSSR 132, 13?16 (1960); Buslaev, V. S., Dokl. Akad. Nauk SSSR 143, 1067?1070 (1962) (in Russian).
2. Merkuriev, S. P. and Faddeev, L. D., Quantum Scattering Theory for Few-Particle Systems, Nauka, Moscow, 1985 (in Russian).
3. Iwai, T., J. Math. Phys. 28, 1315?1326 (1987).
4. Buslaev, V. S. and Merkuriev, S. P., Teor. Mat. Fiz. 5, 372 (1970) (in Russian).
5. Boll�, D. and Osborn, T. A., Phys. Rev. A26, 3062?3070 (1982); Buslaev, V. A. and Chernenko, V. G., Vestnik LGU 2, 16?20 (1987) (in Russian).