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:…for comparing VBM pre-processing algorithms besides comparison to empirically derived information we report a qualitative comparison of our findings with well-established anatomical distribution patterns associated with AD pathology (Braak and Braak, 1991; Frisoni et al., 2010; Hyman et al., 1997).
Category: