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:Surprisingly, recent studies of mutations in the C-terminal interaction domains of mouse BCAR1 (L791P) and BCAR3 (R743A) have shown that the mutants retain many biological activities of the wild-type proteins despite their reported decreased ability to interact (30, 38, 39).
Category: