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 clear that ingressing furrows in both cytokinetic cells and the early fly embryo require membrane trafficking pathways as part of the furrowing mechanism (Lecuit and Wieschaus, 2000; Albertson et al., 2005; Prekeris and Gould, 2008).
Category: