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:The CatWalk system provides a detailed analysis of gait, which has been described in detail elsewhere.(15) A detailed gait analysis was made using the CatWalk system at 3 hours before injury, and at 12 hours; 1, 2, and 3 days; and 1, 2, and 3 weeks after muscle contusion.
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