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:This result is contrary to the previous report from Israel [13] which found a significantly higher seroprevalence to Neospora spp. as horses get older than 10 years of age (because of an increased likelihood of exposure through horizontal transmission over time).
Category: