Spectroscopic monitoring of the BL Lac object AO 0235+164 C. M. Raiteri, M. Villata, A. Capetti, J. Heidt, M. Arnaboldi and A. Magazzù A&A, 464 3 (2007) 871-878 Published online: 11 January 2007 DOI: 10.1051/0004-6361:20066599