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:On the other hand, negative regulation of flavonoidspecific genes by R2R3-MYB or R3-MYB proteins have also been reported in some species (Aharoni et al. 2001; Paolocci et al. 2011; Dubos et al. 2008; Matsui et al. 2008).
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