XMM-Newton observations of Markarian 421W. Brinkmann, S. Sembay, R. G. Griffiths, G. Branduardi-Raymont, M. Gliozzi, Th. Boller, A. Tiengo, S. Molendi and S. ZaneA&A, 365 1 (2001) L162-L167DOI: https://doi.org/10.1051/0004-6361:20000084
