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:In line with our data, junior resident level has been shown to be associated with increased operative time for both open and laparoscopic hernia repair in adults compared with more senior residents.(13) Similarly, junior cardiac surgery fellows were found to have longer operative times compared with the senior fellow when performing coronary artery bypass grafting.
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