Sulphur-bearing molecules in AGB stars - I. The occurrence of hydrogen sulphide T. Danilovich, M. Van de Sande, E. De Beck, L. Decin, H. Olofsson, S. Ramstedt and T. J. Millar A&A, 606 (2017) A124 Published online: 24 October 2017 DOI: 10.1051/0004-6361/201731203