Shape parameters of Galactic open clusters N. V. Kharchenko, P. Berczik, M. I. Petrov, A. E. Piskunov, S. Röser, E. Schilbach and R.-D. Scholz A&A, 495 3 (2009) 807-818 Published online: 30 January 2009 DOI: 10.1051/0004-6361/200810407