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 example, it has been shown that auditory sources result in broad activation patterns in the mid sagittal plane (Van Veen, 1997; Quraan and Cheyne, 2008; Quraan and Cheyne, 2010).
Category: