R.K. Carnegie, R.J. Cashmore, M. Davier, D.W.G.S. Leith, P. Walden, et al.. The imaginary part of the helicity nonflip C = -1 exchange amplitudes in elastic scattering between 6 and 14 GeV.
Physics Letters B, Elsevier, 1975, 58, pp.371-375.
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