Anderson, S. F., Margon, B., Voges, W., Plotkin, R. M., Syphers, D., Haggard, D., Collinge, M. J., Meyer, J., Strauss, M. A., Agüeros, M. A., Hall, P. B., Homer, L., Ivezić, Ž., Richards, G. T., Richmond, M. W., Schneider, D. P., Stinson, G., Vanden Berk, D. E., & York, D. G. (2007). A large, uniform sample of X-ray-emitting active galactic nuclei from the ROSAT all sky and sloan digital sky surveys: the data release 5 sample. Astronomical Journal, 133(1), 313-329. doi:10.1086/509765.