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:Chronic restraint stress (CRS) has been shown to induce cognitive impairment and anxiety- and depressive-like behavior in rodents (Chiba et al. 2012; Huang et al. 2015a, b).
Category: