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:These findings were generated in the presence of counterbalancing and IL-12- and IFN- -mediated Th1-type responses, which are also expressed in BALB/c mice by the second week of infection (30, 45).
Category: