Optical Spectra of Candidate International Celestial Reference Frame
  (ICRF) Flat-Spectrum Radio Sources. III
  In extending our spectroscopic program, which targets sources drawn from the
International Celestial Reference Frame (ICRF) Catalog, we have obtained
spectra for about 160 compact flat-spectrum radio sources and determined
redshifts for 112 quasars and radio galaxies. A further 14 sources with
featureless spectra have been classified as BL Lac objects. Spectra were
obtained at three telescopes: the 3.58-m ESO New Technology Telescope (NTT),
and the two 8.2-m Gemini telescopes in Hawaii and Chile. While most of the
sources are powerful quasars, a significant fraction of radio galaxies is also
included from the list of non-defining ICRF radio sources.
