Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:…2010; Heilman and Smith, 2010), slotfilling with question templates (Popowich and Winne, 2013; Chali and Golestanirad, 2016; Labutov et al., 2015), or implicitly modeled by recent neural models(Du et al., 2017; Zhou et al., 2017b; Yuan et al., 2017; Song et al., 2017; Subramanian et al., 2017).
Category: