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:Executive functioning or meta-cognition was examined using either the Behavior Rating Inventory of Executive FunctionParent (BRIEF) [Gioia et al., 2000] or the Behavior Rating Inventory of Executive Function Adult Version (BRIEF-A) [Roth et al., 2005].
Category: