Detailed chemical composition of Galactic Cepheids - A determination of the Galactic abundance gradient in the 8–12 kpc regionB. Lemasle, P. François, G. Bono, M. Mottini, F. Primas and M. RomanielloA&A, 467 1 (2007) 283-294DOI: https://doi.org/10.1051/0004-6361:20066375