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 Aktmediated phosphorylation downregulates the GTPaseactivating potential of tuberin toward Rheb, which is a potent regulator of mTORC1 (Wullschleger et al., 2006; Guertin and Sabatini, 2007; Yang and Guan, 2007).
Category: