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:Based on the knowledge that NSP1 binds in vitro to all eleven viral mRNAs [4, 15] and the suggestion that it may interact with other viral proteins [13], we hypothesized that such interactions could affect the susceptibility of NSP1 to be degraded.
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