[en] Processing of internal conversion electron spectra obtained on magnetic beta-spectrographs is described. For their mathematical processing UPEAK program is used which applies table task of the model line. On the basis of UPEAK program two approaches to creating the model lines are considered: the method using single spectrum lines as models; and the model construction on the basis of anylitical expressions. From the results of processing L-groups of EIK transitions of 108 keV ¹⁵¹Tb, 123 keV ¹⁵⁴Tb, 165 keV ¹⁴⁹Tb, 271 keV ¹⁵²Tb, 287 keV ¹⁵¹Tb and 344 keV ¹⁵²Tb the conclusion is drawn that relations of EIK L-line intensities could be obtained form the beta-spectrograms using this way of processing with <5% error