found: Work cat.: Liège International Astrophysical Colloquium (24th: 1983). Quasars and gravitational lenses : proceedings ... 1983.
found: NASA.
found: INIS: Thes.
found: McGraw-Hill dict. sci. tech.(Gravitational lens. A massive galaxy whose gravitational field focuses light from a distant quasar near or along its line of sight giving a double or multiple image of the quasar.)
notfound: Web. 3;Gloss. astro. & astrophys.;INSPEC;Macmillan dict. astron.;Dict. astro., space & atmos. phen.;Enc. astro (Satter.);New space encyc.
