On the importance of the few most massive stars: The ionizing cluster of NGC 588 L. Jamet, E. Pérez, M. Cerviño, G. Stasińska, R. M. González Delgado and J. M. Vílchez A&A, 426 2 (2004) 399-413 Published online: 11 October 2004 DOI: 10.1051/0004-6361:20047136