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:, Behera and Yamagata, 2001; Reason, 2002), as well as links between the SST anomalies across the eastern Indian Ocean and regional rainfall (Nicholls, 1989; Frederiksen and Balgovind, 1994; England et al., 2006; Ummenhofer et al., 2008c).
Category: