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:, 2008), high-order partial differential equations (Bai and Feng, 2007; Moraschi et al., 2010), diffusion tensor Enhancing quality in Diffusion Tensor Imaging with anisotropic anomalous diffusion filter
Category: