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:As previously shown for other biological networks (Barabási et al 2011), the degree distribution of the IEMi followed a power law, indicating a scale-free biological network with many proteins with low degree and few proteins with high degree (Fig.
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