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 confirmed the data of others that proliferating basal cells appear in patches or clusters (Moulton et al., 1970; Graziadei and Monti Graziadei, 1979; Monti Graziadei and Graziadei, 1979; Suzuki and Takeda, 1993; Huard and Schwob, 1995).
Category: