Modelling galaxy spectra at redshifts 0.2 ≤z ≤ 2.3 by the [OII]/Hβ and [OIII]/Hβ line ratios M. Contini A&A, 564 (2014) A19 Published online: 28 March 2014 DOI: 10.1051/0004-6361/201322880