H I column densities of z > 2 Swift gamma-ray bursts P. Jakobsson, J. P. U. Fynbo, C. Ledoux, P. Vreeswijk, D. A. Kann, J. Hjorth, R. S. Priddey, N. R. Tanvir, D. Reichart, J. Gorosabel et al. (11 more) A&A, 460 2 (2006) L13-L17 Published online: 16 October 2006 DOI: 10.1051/0004-6361:20066405