First stars - XIV. Sulfur abundances in extremely metal-poor stars M. Spite, E. Caffau, S. M. Andrievsky, S. A. Korotin, E. Depagne, F. Spite, P. Bonifacio, H.-G. Ludwig, R. Cayrel, P. François et al. (8 more) A&A, 528 (2011) A9 Published online: 17 February 2011 DOI: 10.1051/0004-6361/201015926