Evidence for intrinsic absorption in the Swift X-ray afterglows S. Campana, P. Romano, S. Covino, D. Lazzati, A. De Luca, G. Chincarini, A. Moretti, G. Tagliaferri, G. Cusumano, P. Giommi et al. (22 more) A&A, 449 1 (2006) 61-65 Published online: 16 March 2006 DOI: 10.1051/0004-6361:20053823