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:…is most likely long lived as the short-
term (cosmogenic nuclide) erosion rates are within the range of long-term (thermochronometry) rates, suggesting that there has been no significant change in exhumation rates in the past few million
years (Safran et al. 2005, 2006; Wittmann et al. 2009).
Category: