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:…(Chiaravalloti & DeLuca, 2008), but an association has been demonstrated in adequately powered studies (Arnett, Barwick, & Beeney, 2008) and primarily between depression and the cognitive domains of information processing speed and executive functions (Feinstein, 2006; Siegert & Abernethy, 2005).
Category: