3C 20 (Third Cambridge Catalogue of Radio Sources) QSO B0040+517 (Revised and Updated Catalog of Quasi-stellar Objects) 3C 20.0 (Third Cambridge Catalogue of Radio Sources) 4C 51.02 (Fourth Cambridge Survey) PGC 2817481 (فهرس المجرات الرئيسية) LEDA 2817481 (ليون-ميودون قاعدة بيانات خارج المجرة) GRA B0039+51 (Decametric survey of discrete sources in the northern sky. II. Source catalogue in the range of declinations +10 to +20) 3CR 20 (The revised 3C catalogue of radio sources) CTB 6 (A survey of galactic radiation at 960 MC/S) OHIO B 567 (A High-Sensivity Survey of the North Polar Galactic Region at 1415 MHz) S4 0040+51 (The 5-GHz strong source surveys. IV. Survey of the area between declination 35 and 70deg and summary of source counts, spectra and optical identifications) S4 0040+517 (The 5-GHz strong source surveys. IV. Survey of the area between declination 35 and 70deg and summary of source counts, spectra and optical identifications) WB 0040+5147 (A new catalog of 30239 1.4 GHz sources)
