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:Binding of C2 domains (C2A, C2B, and C2AB) of SYT2 to phospholipids was measured according to previous descriptions (Fernandez et al., 2001; Fernandez-Chacon et al., 2002; Shin et al., 2003; Schapire et al., 2008).
Category: