A phenomenological interpretation of open charm production at HERA in terms of the semi-hard approach S.P. Baranov, H. Jung, L. Jönsson, S. Padhi and N.P. ZotovEur. Phys. J. C, 24 3 (2002) 425-437DOI: https://doi.org/10.1007/s10052-002-0957-3