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:In the course of the proof in [2], the authors prove that in G(n, p), for suitable values of p, a number of events that deal with the number of edges spanned by a vertex set of a given size occur with high probability.
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