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:On the other hand, the AA can be converted to arylhydroxylamines primarily as a result of reactions catalyzed by the cytochrome P450 monooxygenase (CYP1) family, in particular CYP1A2 in the liver (Kim and Guengerich 2005).
Category: