3 It also contains quite a few errors; for example, about 60 stories in the<cite> (Perret et al., 2016)</cite> dataset have no discourse structure in them at all and consist of only one DU. We eliminated these from the Perret 2016 data set that we used in our comparative experiments below, as these sto-3 There is also on the STAC website an updated linguistic only version of the STAC corpus.