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:Imagebased models yielded joint kinematics, net joint moments, hip joint forces, muscle activation patterns and bone strains in the proximal-lateral femoral shaft in agreement with earlier studies (Aamodt et al., 1997; Bergmann et al., 2001; Inman et al., 1989; Kadaba et al., 1989; Stacoff et al., 2005).
Category: