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:Anticancer activities of antioxidants are investigated thoroughly revealing the most common mechanism of action as the fenton reaction in which antioxidants at higher concentrations act as oxidants to induce apoptotic cell death in cancer cells (Matés and Sánchez-Jiménez 2000).
Category: