Notes.From left to right: target name, period, J, H, K mean magnitudes, iron abundance, distance modulus and Galactocentric distance. Notes on the photometric data: ^(a) mean magnitudes provided by Monson & Pierce (2011) transformed into the 2MASS photometric system using the relations given in their Table 1. ^(b) Mean magnitudes provided by Laney & Stobie (1992) and Laney (priv. comm.) transformed into the 2MASS photometric system using the relations given by Koen et al. (2007). The objects marked with a ^(†) (Laney, priv. comm.) do not have a complete coverage of the light-curve (the number of phase points ranges from 4 to 14). ^(c) Mean magnitudes based on single-epoch measurements from the 2MASS catalogue and the NIR template light curves provided by Soszyński et al. (2005). ^(d) Classical Cepheids for which the spectroscopic iron abundance is measured for the first time. ^(e) The weighted mean true distance moduli. The errors account for uncertainties affecting mean magnitudes and for the intrinsic dispersion of the adopted NIR PW relations. ^(f) The weighted mean Galactocentric distances were estimated assuming R_G = 7.94 ± 0.37 ± 0.26 kpc (Groenewegen et al. 2008). The errors account for uncertainties affecting both the solar Galactocentric distance and the heliocentric distances.