Wanders I., B.M. Peterson, D. Alloin, T.R. Ayres, J. Clavel, D.M. Crenshaw, K. Horne, G.A. Kriss, J.H. Krolik, M.A. Malkan, and H. Netzer, The Astrophysical Journal Supplement Series 113, 69-88 (1997).