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:The following murine mAb’s were used: 3BD10 (epitope TSHR amino acid residues 25–51) (27) and 2C11 (epitope containing amino acid residues 354–359) (29).
Category: