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:We performed two different searches under the HKI + G model (previously estimated by Modeltest excluding from the dataset the outgroup sequences) assuming the two ND4 specific divergence rates proposed by Pinho
et al. (2007) for lacertids.
Category: