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:Differences between central (aortic) and brachial BP could be clinically important, as central BP is more closely correlated with target organ damage in hypertension [4]; is differentially influenced by antihypertensive therapy compared with brachial BP [5]; and may be a superior predictor of cardiovascular events than brachial BP [6].
Category: