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:Although our results are in accordance with earlier studies giving prevalence rates between 4 and 8% using NIH criteria (Knochenhauer et al., 1998; DiamantiKandarakis et al., 1999; Michelmore et al., 1999; Asuncion et al., 2000; Azziz et al., 2004; March et al., 2010; Moran et al., 2010a,b; Sanchon et al., 2012), we found higher figures than previous studies using Rotterdam criteria (Chen et al.
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