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:The barn owl shows a third type of pattern; there is only a small increase of the hair cell number in a cross section in the basal half of the papilla, followed by a more rapid but continuous increase in the apical half (Fischer et al., 1988; Smith et al., 1985).
Category: