Sulphur-bearing species in the star forming region L1689N V. Wakelam, A. Castets, C. Ceccarelli, B. Lefloch, E. Caux and L. Pagani A&A, 413 2 (2004) 609-622 Published online: 18 December 2003 DOI: 10.1051/0004-6361:20031572