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:exposure in those IL-6 KO mice and found a significantly higher number of eosinophils in the airway in these mice than in wild-type mice (data not shown), corroborating the observations that were previously published using the OVA model (21, 22).
Category: