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 recommended diet was formulated by Excel Eiyo-kun software version 4.0–6.0 for Food Frequency Questionnaire, which analyzes each participant’s diet information collected on the Food Frequency Questionnaire Based on Food Groups version 2.0–3.5 (KENPAKUSHA, Tokyo, Japan).
Category: