“…In support of our approach we also highlight that the use of [α/Fe] as a single parameter involving a set of elements is also justified by the findings of Johansson et al (2012), who find that the correlations of [O/Fe], [Mg/Fe], [C/Fe] with velocity dispersion are identical for ETGs. In general, models capable of predicting the effects of α-elements on the full optical spectrum of stellar populations are starting to become less rare, see Coelho et al (2007), Koleva et al (2008b), Walcher et al (2009), Percival et al (2009, Vazdekis et al (2011), Conroy & van Dokkum (2012, Prugniel & Koleva (2012), Vazdekis et al (2015).…”