Red giants in open clusters - IX. NGC 2324, 2818, 3960 and 6259 J.-C. Mermilliod, J. J. Clariá, J. Andersen, A. E. Piatti and M. Mayor A&A, 375 1 (2001) 30-39 Published online: 15 August 2001 DOI: 10.1051/0004-6361:20010845