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:Surveys, based on The Organisational Values Questionnaire (OVQ) developed by Reino [9] and Resistance to Change Scale (RTC) developed by Oreg [8], were sent out to 4 hospital wards in a medical clinic in Sweden.
Category: