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:CD47 is expressed widely in both hematopoietic cells, including three subtypes of cDCs (Supplemental Figure S3), and nonhematopoietic cells, however.(20,24) We therefore next For personal use only.
Category: