Sulphur and zinc abundances in Galactic halo stars revisited P. E. Nissen, C. Akerman, M. Asplund, D. Fabbian, F. Kerber, H. U. Käufl and M. Pettini A&A, 469 1 (2007) 319-330 Published online: 11 April 2007 DOI: 10.1051/0004-6361:20077344