The XMM-Newton view of NGC 6251 M. Gliozzi, R. M. Sambruna, W. N. Brandt, R. Mushotzky and M. Eracleous A&A, 413 1 (2004) 139-144 Published online: 17 December 2003 DOI: 10.1051/0004-6361:20034053