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:Line and hard were chosen because they have served in various WSD studies to date (e.g., Leacock et al., 1993) and a corpus of occurrences of these words from the Wall Street Journal corpus was generously made available for comparison.2 Serve, another word frequently used in these studies, did not‚Ä¶
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