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:PKBR1, however, also becomes activated upon cAMP stimulation by phosphorylation in both the AL site by PdkA and in the HM site by TorC2 (Kamimura et al., 2008, 2010; Cai et al., 2010; Liao et al., 2010).
Category: