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:Thirty-one additional bindin sequences of E. viridis and 16 of E. vanbrunti (accession numbers AY451276–AY451323, McCartney and Lessios 2004) were included in the analyses.
Category: