Blank field sources in the ROSAT HRI Brera multiscale wavelet catalog M. Chieregato, S. Campana, A. Treves, A. Moretti, R. P. Mignani and G. Tagliaferri A&A, 444 1 (2005) 69-77 Published online: 21 November 2005 DOI: 10.1051/0004-6361:20041726