Luminosity-dependent unification of active galactic nuclei and the X-ray Baldwin effect C. Ricci, S. Paltani, H. Awaki, P.-O. Petrucci, Y. Ueda and M. Brightman A&A, 553 (2013) A29 Published online: 25 April 2013 DOI: 10.1051/0004-6361/201220324