On the artificial nature of aperiodic variability in XMM-Newton observations of M 31 X-ray sources and the ultraluminous X-ray source NGC 4559 ULX-7R. Barnard, S. Trudolyubov, U. C. Kolb, C. A. Haswell, J. P. Osborne and W. C. PriedhorskyA&A, 469 3 (2007) 875-879DOI: https://doi.org/10.1051/0004-6361:20066333
