Near-infra-red spectroscopic ages of massive star clusters in M 82 A. Lançon, J. S. Gallagher III, M. Mouhcine, L. J. Smith, D. Ladjal and R. de Grijs A&A, 486 1 (2008) 165-176 Published online: 15 May 2008 DOI: 10.1051/0004-6361:200809439