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:, 2008), and Srebp1/2 are known to interact with Hmgb1/2; their activity has been reported to be enhanced by Hmgb1 (Najima et al., 2005).
Category: