XMM-Newton observations of the Lockman Hole - V. Time variability of the brightest AGN S. Mateos, X. Barcons, F. J. Carrera, M. J. Page, M. T. Ceballos, G. Hasinger and A. C. Fabian A&A, 473 1 (2007) 105-120 Published online: 16 July 2007 DOI: 10.1051/0004-6361:20077909