J. Kruijssen, F. Pelupessy, H. Lamers, S. Zwart, N. Bastian, und V. Icke. (2011)cite arxiv:1112.1065Comment: 15 pages, 9 figures, 2 tables; Accepted for publication in MNRAS. A movie of the full time sequence in Figure 1 can be found at http://www.mpa-garching.mpg.de/~diederik/1m11clusters.html.