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:, 2000) (serine 102/glutamine 103), which corresponds to the serine 88/glutamine 89 of HMGA1, phosphorylated by ATM (Pentimalli et al., 2008).
Category: