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:We used expert consensus to identify Diagnosis Related Group (DRG), Current Procedural Terminology (CPT), and ICD9-CM codes relevant to diabetic foot conditions to adapt the classification scheme of the IWG on the diabetic foot.(8) The risk categories were then ordered by severity into levels from 0 (lowest, with no codes of interest) to 6 (highest).
Category: