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:Each of the four annotationbased GO term similarity approaches, namely Resnik, Lin, relevance and Li et al., is implemented with four known IC-based non-direct functional similarity measures (Avg, Max, BMA and ABM).
Category: