Left: results of the pulse-to-pulse analysis of the INTEGRAL observation of rev. 0912. The photon index Γ with fixed E_rolloff = 15.5 keV and the cyclotron line energy E_cyc are plotted as a function of the individual pulse height. The vertical error bars indicate 1σ-uncertainties. The horizontal error bars correspond to the pulse-height bins used to accumulate the spectra. The solid lines indicate linear fits to the data. Right: same but for the RXTE observations. In the data for the upper panel E_rolloff was fixes to 15.2 keV.