Ef_E spectrum of X Per observed by INTEGRAL. The best-fit spectra of the three different models discussed in the text and their residuals are shown. Data from ISGRI (black), JEM-X (red) and SPI (green) instruments were used. The contribution of the single model components is also shown. For the model by Coburn et al. (2001) (middle panel), we also show (shadowed area) the effect of including an absorption-like line, which is required by the specific continuum.