Parametrisation of the Hβ+[OIII]+FeII (left and middle panels) and Hα+[NII]+[SII] (right) regions of z ∼ 2 QSO1 from the sample of Shen (2016). The red lines show the best-fit from multiple systemic, outflow, and broad Gaussian profiles to the line features, together with a single power law to the continuum and one (two) template(s) to the FeII features (see text). Each curve with a different colour represents a distinct Gaussian set (or a FeII template) with the same kinematic properties, as labelled in the figure. In the central panel we show for each target the spectrum around the Hβ+[OIII] lines after the subtraction of the continuum. The red curve represents the best-fit retrieval model from MC fits, and the shaded area encompass 68% of the MC sample; the black curve shows the [OIII] best fit obtained by Shen (2016).