SIMBAD references

We used the Near Infrared Camera on Keck I to obtain K_s-band images of four candidate high-redshift radio galaxies selected using optical and radio data in the NOAO Deep Wide-Field Survey in Boötes. Our targets have 1.4 GHz radio flux densities greater than 1 mJy, but are undetected in the optical to ≳24 Vega mag. Spectral energy distribution fitting suggests that three of these objects are at z > 3, with radio luminosities near the FR-I/FR-II break. The other has photometric redshift z_phot= 1.2, but may in fact be at higher redshift. Two of the four objects exhibit diffuse morphologies in K_s-band, suggesting that they are still in the process of forming.