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:Additionally, it is important to consider that most studies linking higher vancomycin MIC values to poorer therapeutic outcome have used Etest.(16,64,65) When treating individual patients with daptomycin, clinicians should also be aware that there are rare daptomycin nonsusceptible isolates present in this population of organisms.
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