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:A contribution of MiRP1 to native IKr is debatable however (28, 29), and it has been suggested that MiRP1 is unlikely to associate significantly with hERG in areas of the heart outside of the conduction system (30, 31).
Category: