Rest-frame SED modelling for the three IFRS whose redshifts were determined in this work. All templates are shifted to the rest-frame and scaled in luminosity to match the photometric data points shown by red crosses (S212), orange triangles (S265), and purple circles (S713). While the SED templates of star forming galaxy Arp 220 (green dashed line) and Seyfert galaxy Mrk 231 (olive dashed-dotted line) clearly disagree with the available photometric data, the templates of the radio-loud quasar 3C 273 (black solid line) and the compact steep spectrum (CSS) source 3C 48 (blue dotted line) fulfill the requirements.