Spectroscopic parameters for 451 stars in the HARPS GTO planet search program - Stellar [Fe/H] and the frequency of exo-NeptunesS. G. Sousa, N. C. Santos, M. Mayor, S. Udry, L. Casagrande, G. Israelian, F. Pepe, D. Queloz and M. J. P. F. G. MonteiroA&A, 487 1 (2008) 373-381DOI: https://doi.org/10.1051/0004-6361:200809698
