SIMBAD references

We present the results of a 230GHz survey of quasars and BL Lacertae objects performed with the SEST. The sample consists of objects with flat radio spectra and is taken from various radio surveys. Repeated observations for individual sources indicates variability by factors of 2-5 within a single night. Comparing measurements over longer periods, even changes by factors of 10-25 at 230GHz have been observed. The present catalog contains the 130 brightest objects whose 230GHz flux densities are above 500mJy most of the time. This, and their declination below +20°, makes them useful candidates for future pointing sources at southern submillimeter telescopes. First measurements of flux densities at 345GHz are given for six objects.