On the formation of massive stellar clusters G. Tenorio-Tagle, J. Palouš, S. Silich, G. A. Medina-Tanco and C. Muñoz-Tuñón A&A, 411 3 (2003) 397-404 Published online: 17 November 2003 DOI: 10.1051/0004-6361:20031387