1. R. G. Newton:Scattering Theory of Waves and Particles (McGraw Hill, New York, N.Y., 1966).
2. P. M. Morse andH. Feshbach:Methods of Theoretical Physics (McGraw Hill, New York, N.Y., 1953).
3. E. Vogt andG. H. Wannier:Phys. Rev. (N.Y.),95, 1190 (1954).
4. R. M. Spector:J. Math. Phys.,5, 1185 (1964).
5. W. Gordon:Z. Phys.,48, 180 (1928).