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:…were reviewed by an independent radiologist regarding the degree of coronoid involvement (inclusion/ exclusion), the degree of osteoarthritis according to Broberg and Morrey (1986), and signs of prosthetic loosening according to the method developed by Popovic et al. (2007) for the proximal radius.
Category: