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 schizophrenic patients, particularly those with recent psychotic exacerbations, psy-
chotic symptoms are associated with dopaminergic hyperactivity (Abi-Dargham et al. 2000; Breier et al. 1997b; Laruelle et al. 1996, 1999).
Category: