FIRST-2MASS Sources Below the APM Detection Threshold: A Population of   Highly Reddened Quasars
  We have constructed a sample of bright near-infrared sources which are detected at radio wavelengths but undetected on the POSS I plates in order to search for a population of dust-obscured quasars. Optical and infrared spectroscopic followup of the sample has led to the discovery of seventeen heavily reddened quasars (B-K>6.5), fourteen of which are reported here for the first time. This has allowed us to define a region in the R-K, J-K color plane in which 50% of the radio-selected objects are highly reddened quasars. We compare the surface density of this previously overlooked population to that of UVX- radio-selected quasars, finding that they make up ~20% of the total quasar population for K < 15.5. 
Eilat Glikman (1), Michael D. Gregg (2,3), Mark Lacy (4), David J.   Helfand (1), Robert H. Becker (2,3), Richard L. White (...