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:If a cerebral vasculitis of autoimmune origin is suspected, there has to be first a pretest verification: predominantly females, young, no previous history of cardiovascular disease, focal or multiple lesions evidenced in a brain MRI or CT [17].
Category: