Selected high-resolution (R ~ 38   000) UVES spectra of Galactic Cepheids in our sample. From top to bottom are plotted the spectra of V340 Ara ([Fe/H]  = 0.53 ± 0.09), MZ Cen ([Fe/H]  = 0.27 ± 0.10) and V773 Sgr ([Fe/H]  = 0.11 ± 0.06). The apparent visual magnitude and the S/N in the spectral range λ ~5650–7500 Å (red arm) are also labeled. The vertical dashed lines display selected Fe I (λλ5930.17, 5934.66, 5952.73, 5956.7, 5975.35, 5976.78, 5983.69, 5984.79, 5987.05, 5997.78 Å) and Fe II (λλ5932.06 and 5991.37 Å) lines included in our abundance analysis (see Table 1 and Romaniello et al. 2008).