Mass segregation in young Magellanic Cloud star clusters: Four clusters observed with HST D. Gouliermis, S. C. Keller, M. Kontizas, E. Kontizas and I. Bellas-Velidis A&A, 416 1 (2004) 137-155 Published online: 26 February 2004 DOI: 10.1051/0004-6361:20031702