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 animals, supplementation with antioxidants seems to protect against CP-induced side effects (Greggi-Antunes et al., 2000; Mansour et al., 2002; Sueishi et al., 2002).
Category: