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:Similar results were previously reported in the ischemic striatum and fronto-parietal cortex, the core and the penumbra of the ischemia induced by MCAo, of rats with a similar survival and neurological impairment (Vannucchi et al., 2005, 2007).
Category: