Massive star-formation rates of γ-ray burst host galaxies: An unobscured view in X-rays D. Watson, J. Hjorth, P. Jakobsson, K. Pedersen, S. Patel and C. Kouveliotou A&A, 425 2 (2004) L33-L36 Published online: 21 September 2004 DOI: 10.1051/0004-6361:200400058