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:Examples of possible modifiers include loci encoding xenobiotic enzymes, NAT1, NAT2, GSTM1, GSTT1 (7–9), or ATM, ataxia-telangiectasia-associated locus (10).
Category: