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 perisylvian speech-language region in humans is known to be predominantly larger in the left hemisphere of righthanded individuals (LeMay 1976; Galaburda et al. 1978; Hepper et al. 1991; Foundas et al. 1994; LeMay 1999; Shapleske et al. 1999; Naidich et al. 2001; Hamilton et al. 2007).
Category: