Integrated spectral analysis of 18 concentrated star clusters in the Small Magellanic Cloud A. E. Piatti, J. F. C. Santos Jr., J. J. Clariá, E. Bica, A. V. Ahumada and M. C. Parisi A&A, 440 1 (2005) 111-120 Published online: 19 August 2005 DOI: 10.1051/0004-6361:20052982