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:These definitions rest on the assumption that flipped teaching alters traditional instruction so that deeper levels of learning can take place in class rather than rely on homework (Gannod et al., 2008; Mason et al., 2013; McLaughlin et al. , 2014; Prober & Khan, 2013; Strayer, 2012; Tucker, 2012).
Category: