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:Cleft surgeons commonly present 10 consecutive lip repairs, although the basis for this sample size remains unproven (McComb, 1985; Boo-Chai, 1987; Lohmander-Agerskov et al., 1990; Bertolini et al., 2000; Haramoto et al., 2000; Braumann et al., 2001; AlQattan, 2002; Braumann et al., 2002; Lee et al., 2004; McComb, 2009; Tindlund et al., 2009; Grasseschi, 2010).
Category: