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:…by which DREAM transactivates the GFAP promoter in response to calcium is likely to involve changes in protein conformation (Carrión et al., 1999; Osawa et al., 2001, 2005) that could be stabilized by interactions with other proteins bound in close proximity (Rivas et al., 2004;…
Category: