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:Network-based studies gave rise to the disease module hypothesis (Barabási et al 2011; Vidal et al 2011) where diseases with an overlap in biological networks show significant symptom similarity and common disease mechanisms, whereas diseases residing in separated network neighborhoods are…
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