... GPS radio sources . ... GPS (Gigahertz Peaked-Spectrum) galaxies and quasars are powerful radio sources with a convex radio spectrum that peaks between 0.5 and several tens of GHz (observer's frame). ... The samples studied often include quasars with a peak in the radio spectrum (hereafter referred to as FSRQ - Flat Spectrum Radio Quasars). ... In total, the sample contains about 5000 sources.We selected 467 objects with convex radio spectra, which we considered to be GPS candidates. ...