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:During an infection with another alphaherpesvirus, HSV-1, in mice, it has been reported that CCL3 attracts NK cells [16], CCL2 recruits monocytes [17], and CCL5 recruits monocytes, NK cells, and PMNs [18] while CXCL9 recruits T-cells to the sites of infection [16, 19].
Category: