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:…hair cells (which differ from ‘short’ hair cells with respect to the location of the stereovillar bundle within the apical hair cell surface; Smith et al., 1985) are present in the two species, we measured the distance of the stereovillar bundle from the hair cell border (in the…
Category: