Survey of instantaneous 1-22 GHz spectra of 550 compact extragalactic objects with declinations from to Y. Y. Kovalev, N. A. Nizhelsky, Yu. A. Kovalev, A. B. Berlin, G. V. Zhekanis, M. G. Mingaliev and A. V. BogdantsovAstron. Astrophys. Suppl. Ser., 139 3 (1999) 545-554DOI: https://doi.org/10.1051/aas:1999406