The HARPS search for southern extra-solar planets - VI. A Neptune-mass planet around the nearby M dwarf Gl 581X. Bonfils, T. Forveille, X. Delfosse, S. Udry, M. Mayor, C. Perrier, F. Bouchy, F. Pepe, D. Queloz and J.-L. BertauxA&A, 443 3 (2005) L15-L18DOI: https://doi.org/10.1051/0004-6361:200500193
