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:Although Arpp/Ankrd2 has been reported to be localized mainly in the I-band of striated muscle (Tsukamoto et al. 2002; Miller et al. 2003), a recent study has revealed that Arpp/Ankrd2 can interact with nuclear proteins, including premyelocytic leukemia protein (PML), p53 and YB-1, in vitro (Kojic…
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