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:Our proposed algorithm seeks to improve upon the performance of several existing algorithms, including ABS [47, 48, 18, 43], local principal component analysis (PCA) [5], local adaptive singular value cancellation (aSVC) [1] and non-local aSVC [1, Section 3.
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