The comparison between the equivalent width (left) and the normalised flux (right) of the main emission lines measured in this work (TW) with those available in the literature from Jansen et al. (2000; J; upper panel), Moustakas & Kennicutt (2006; MK; middle panel), and Moustakas et al. (2010; M; lower panel). Different colour codes are used for the different emission lines: red symbols for Hα; blue for Hβ, green for [Nii]6548 and [Nii]6584 Å, cyan for [Oiii] and 5007 Å, magenta for [Oii] 3727 Å, and yellow for [Sii] 6717 and 6731 Å (the two lines composing a doublet are plotted with the same symbol). The solid line shows the 1:1 relationship.