We checked that the effect of finite mass corrections to the angular distribution , the use of m h instead of the quark mass m in the threshold factor , as well as the scaling violations in the fragmentation function due to the reduced ( i.e. s → sz ) CM hadronic energy , have a negligible impact on our results . The effect of the ISR correction is displayed in Fig . 3 , where BELLE data for D * + → D 0 π + are displayed before and after the ISR correction has been applied , both in x and moment space . The ALEPH data are also shown in moment space . We see that the corrected spectrum for BELLE is harder and lower in normalization than the uncorrected one . This is to be expected , since ISR lowers the available hadronic energy , thus softening the spectrum and increasing the cross section at the same time . We can also see that the effect for BELLE is not large , but nonetheless not negligible . It is instead much less prominent , up to the point of being negligible , for the ALEPH data taken on the Z 0 peak , as expected .