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:Moreover, divergent transcription, defined by detection of populations of low abundance small RNAs (19–25 nts) generated by nonoverlapping (separated by approximately 250 bps) bidirectional transcription, was detected at the majority of transcriptional start sites (TSSs) in mouse embryonic stem cells (mESCs) (5).
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