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:The subjects with AD met the Diagnostic and Statistical Manual of Mental Disorders (Third Edition Revised) (DSM-IIIR) criteria of dementia [14] and were clinically diagnosed by a dementia investigative team as having probable late-onset AD according to criteria from the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association (NINCDS-ADRDA) [15].
Category: