Metallicities for six nearby open clusters from high-resolution spectra of giant stars - [Fe/H] values for a planet search sampleN. C. Santos, C. Lovis, J. Melendez, M. Montalto, D. Naef and G. PaceA&A, 538 (2012) A151DOI: https://doi.org/10.1051/0004-6361/201118276