The chemical enrichment of long gamma-ray bursts nurseries up to z = 2 S. D. Vergani, J. Palmerio, R. Salvaterra, J. Japelj, F. Mannucci, D. A. Perley, P. D’Avanzo, T. Krühler, M. Puech, S. Boissier et al. (5 more) A&A, 599 (2017) A120 Published online: 10 March 2017 DOI: 10.1051/0004-6361/201629759