XMM-Newton monitoring of X-ray variability in the quasar PKS 0558-504 M. Gliozzi, W. Brinkmann, P. T. O'Brien, J. N. Reeves, K. A. Pounds, M. Trifoglio and F. Gianotti A&A, 365 1 (2001) L128-L133 Published online: 15 January 2001 DOI: 10.1051/0004-6361:20000207