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:Concerning age, other studies that included dogs treated with trilostane or mitotane have reported similar results.(33,35) In contrast, age was not reported to be associated with survival in another study that included dogs treated with trilostane, and our results are consistent with theirs.
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