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:These results illustrated the importance of sociality in coping with disease and parasitism (Rosengaus et al. 1998, 2000; Rosengaus and Traniello 2001; Traniello et al. 2002; Shimizu and Yamaji 2003; Maekawa et al. 2005; Calleri et al. 2006; Wilson-Rich et al. 2007; Yanagawa and Shimizu 2007).
Category: