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:The effort to develop new treatments for ALS has led to repeated failure since the demonstration that riluzole extended survival.[3] Despite initially encouraging results from a Phase II trial, which suggested beneficial effects on ALSFRS-R and survival,[27] the recent negative results of the dexpramipexole Phase III study is yet another disappointing example.
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