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:[8,18] These signs as well as others could be used to help develop a diagnostic algorithm, as proposed by Nguena et al, to help clinicians identify OSSN and know when to appropriately refer for more specialized care.[8] Tumor depth could also provide a simple clinical measure to use in order to differentiate between high risk OSSN and benign lesions.
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