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:Significant decrease in CTFC was observed in the culprit vessel compared to the non-culprit vessel within the ic group in all subgroups (STEMI vs. NSTEACS, visible vs. no visible thrombus, and TIMI flow 0-1 vs. 2-3).
Category: