[F/Fe] and [F/H] against [Fe/H] (top) and age (bottom). The data points are measurements for OCs as well as field stars, and the lines are predicted from theoretical models. The OCs from our previous sample are shown as black hexagons. The figure shows the models that allow F to form from both LIMS and massive stars (solid lines) and the models that only allow F to form from AGB stars (dashed lines).