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:Measure
The survey (The Autism Awareness Survey) was created to identify respondent knowledge about autism; it was a modification and update of a survey of autism knowledge created by Stone (1987) and later adapted by Heidgerken et al. (2005).
Category: