1999ApJ...516..141P

This paper selects potential EGRET (high-energy γ-ray) identifications from a catalog of radio sources with strong X-ray emission (ROSAT/Greenbank, RGB catalog). In particular, we look for weak to moderate radio sources with strong X-ray emission. Such a search is designed to locate high-frequency peaked BL Lacertae objects (HBLs) and intermediate-frequency peaked BL Lacertae objects (IBLs), as well as Galactic magnetized black holes, all of which have been argued in the literature to harbor relativistic jets capable of high-energy γ-ray emission. We find three new HBL/IBL BL Lacertae identifications (and one marginal IBL BL Lacertae identification), one compact Galactic object (possibly a magnetized black hole), and three other radio sources of unknown identity.