1. T.A. Brody, J. Flores, J.B. French, P.A. Mello, A. Pandey, S.S.M. Wong, Rev.Mod.Phys. 53, 385 (1981)
2. R.R. Whitehead, A. Watt, D. Kelvin and A. Conkie, Phys.Lett. jSB, 9 (1978); J.J.M. Verbaarschot and P.J. Brussaard, ibid. 86B, 155 (1979); S.M. Grimes and S.D. Bloom, Phys.Rev. C23, 1259 (1981)
3. C. Mahaux and H.A. Weidenmüller, Ann.Rev.Nucl. Part.Sci 29, 1 (1979)
4. A.M. Lane and J.E. Lynn, Proc.Phys.Soc. London LXX 8-A, 557 (1957); L. Dresner, Proc.Int.Conf. on Neutron Interactions with the Nucleus, Columbia University 1957. Report CU 175, p.71, New York: Columbia Univ. (1957); P.A. Moldauer, Phys. Rev. J_23, 968 (1961) and Phys.Rev. C14, 764 (1976); G. Reffo, F. Fabbri, H. Gruppelaar, Lett. Nuovo Cimento 17, 1 (1976); H. Gruppelaar, G.Reffo, Reprint Technical Notes, Nucl.Sci.Eng. 62. 756 (1977). An interesting recent contribution to this question is T.H. Seligman, Z. Phys. A305, 69 (1982)
5. P.A. Moldauer, Nucl.Phys. A344, 185 (1900)