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:Several of these proteins take part in cellular detoxification and antioxidant defence, such as glutathione S-transferases (GSTs), carbonic anhydrase III (CAIII) and CuZn-superoxide dismutase [42, 47, 48].
Category: