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:…ranged in age between 8 and 12 weeks and weighed between 22 and 35 g.
Auditory Function
Auditory function was evaluated using the auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) as described in our earlier reports (Chen et al. 2010; Jamesdaniel et al. 2008).
Category: