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:For each mapped RNA-seq library, we then estimated the expression level of each transcript with its respective error, for each allele in a Cast/EiJ×C57Bl/6J diploid transcriptome using MMSEQ (Turro et al., 2011).
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