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:BLASTX searches were conducted against an in-house database comprised of NCBI RefSeq plant and microbe peptide databases (release 51) combined with peptide sequences from marine taxa whose genomes were sequenced using single-cell sequencing (Swan et al., 2011; Swan et al., 2013).
Category: