HCN(1–0) enhancement in the bar of NGC 2903 S. Leon, S. Jeyakumar, D. Pérez-Ramírez, L. Verdes-Montenegro, S. W. Lee and B. Ocaña Flaquer A&A, 491 3 (2008) 703-711 Published online: 01 October 2008 DOI: 10.1051/0004-6361:200810162