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:This may be due to poor cell cycle synchronization in the former or to a higher level of Mrc1 protein in hsk1-89 cells, which can potentially cause adverse effects on signal enrichment in a ChIP assay (41).
Category: