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:Our CSU diagnostic evaluation, described in greater detail elsewhere (Carroll et al., 1981) consists of a 14-day drug-free period (patients are completely free of psychotropic medications during this period): several clinical interviews; a structured diagnostic interview, the Schedule for Affective…
Category: