Odderon and photon exchange in electroproduction of pseudoscalar mesons E.R. Berger, A. Donnachie, H.G. Dosch, W. Kilian, O. Nachtmann and M. RueterEur. Phys. J. C, 9 3 (1999) 491-501DOI: https://doi.org/10.1007/s100520050043