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:A surface-exposed pocket of SspA that includes the Tyr92 residue is important for SspA activity [42] (Figure 5A), raising the question of whether phosphorylation of Tyr92 affects SspA activity.
Category: