Positron spectra from internal pair conversion observed in + collisions S. Heinz, E. Berdermann, F. Heine, O. Joeres, P. Kienle, I. Koenig, W. Koenig, C. Kozhuharov, U. Leinberger, M. Rhein, A. Schröter and H. Tsertos The ORANGE Collaboration at GSIEur. Phys. J. A, 9 1 (2000) 55-61DOI: https://doi.org/10.1007/s100500070055