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:Anti-PLA2R antibodies is an important factor in the occurrence of MN.(31) In general, anti-PLA2R antibodies is considered as a useful biomarker for early diagnosis and prognosis in patients with MN.
Category: