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The dierential pp ! nn charge-exchange cross section has been measured at the CERN Low Energy Antiproton Ring (LEAR), at two incident p momenta, 601 and 1202 MeV/c. The main features of the dierential cross-section near the forward direction, i.e. a sharp peak at 0 scattering angle followed by an energy dependent dip-bump structure, are conrmed and measured with good precision and high statistical accuracy. The data show v ery clearly that the shape of the cross-section is a manifestation of the pion-exchange amplitude, and a simple extrapolation to the pion pole already indicates that the pion-nucleon coupling constant f 2 c can be determined with good precision.