Kumar, P; Chand, H; Srianand, R; Stalin, C. S; Petitjean, P; Gopal-Krishna
(Oxford University Press on behalf of the Royal Astronomical Society, 2018-10)
A small subset of optically selected radio-quiet quasars showing weak or no emission lines may turn out to be the elusive radio-quiet BL Lac objects, or simply be radio-quiet QSOs with a still-forming/shielded broad line ...