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:It is now evident that centrosomes play a crucial role in the timing of mitotic events, such as the cyclin B degradation in early Drosophila embryos and exit of cytokinesis in animal cells (8, 9).
Category: