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:In general, our results on the effect of contact compounds from grapes differ from those published by other authors (Maher and Thiery 2004a, 2006; Maher et al. 2006; Moreau et al. 2008).
Category: