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:Although there is limited evidence concerning the role of PPAR-Œ± on memory and cognition, our results are in line with previous studies showing that systemic administrations of OEA, URB597, or WY14643 (a PPAR-Œ± agonist) facilitate learning processes and enhance retention of inhibitory avoidance task through activation of PPAR-Œ± (Campolongo et al., 2009a; Mazzola et al., 2009).
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