The ([O iii]λ4959, λ5007+[O ii]λ3727)/Hβ versus [O iii]λ4959, λ5007/[O ii]λ3727 diagram for the sample considered in this paper. Also shown is the McGaugh (1991) calibration of tracks with constant metallicity. Models with oxygen abundances lower than 12 + log(O/H) ≲ 8.4 are shown as dashed lines, those with higher oxygen abundances are shown by continuous lines. Symbols are the same as in the right-hand panel of Fig. 5.