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:Other cross-linking experiments and RNA protection studies with functional elongation complexes suggest that NusA likely makes contacts near the RNA exit channel, around the β-flap domain (41, 71, 126, 138); conceivably, an extended conformation of the NusA protein contacts both regions, not unlike the wide reach of σ70.
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