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:DTI derived diffusion parameters, such as fractional anisotropy (FA), have been widely used to assess white matter microstructure [16, 17, 25], and has previously been used to detect traumatic brain injury in athletes [6, 10, 18, 49], and military personal following blast-related brain injury [29].
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