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:…and SR19 (5′-[880]GGGATAGAGACACCAATACC-3′) to yield a 740-bp fragment for exon 3 (the nucleotide numbers in square brackets refer to the deposited genomic DNA sequences) (Ohye et al. 1998; GenBank accession numbers AB017547, for exons 1 and 2, and AB017548, for exon 3).
Category: