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:Inclusion criteria were having erosions detected by endoscopy at enrollment into this study or having a past history of RE, and having reflux symptoms at enrollment into this study, which could be evaluated using the 8-item Short-Form Health Survey (SF 8TM, Japanese translation) [12, 13] and the Frequency Scale for the Symptoms of GERD (FSSG) [14].
Category: