Absorption spectrum of the quasar HS1603+3820 - I. Observations and data analysis A. Dobrzycki, M. Nikolajuk, J. Bechtold, H. Ebeling, B. Czerny and A. Różańska A&A, 476 3 (2007) 1205-1217 Published online: 09 October 2007 DOI: 10.1051/0004-6361:20077342