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:Thus far, increases in the diagnostic sensitivity of CA125 by using marker panels have been moderate (5–10%), often at the expense of decreases in specificity, and vice versa (Tuxen et al, 1995; Meyer and Rustin, 2000; Bast, 2003; Zhang et al, 2004).
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