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:To follow up that study, we recently investigated in vitro RAG-mediated cleavage of these plasmid substrates, using ligation-mediated PCR (LM-PCR) to detect blunt signal end breaks (SEBs) at the 23-RSS or the cRSS [24] (Fig.
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