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:) [83, 87, 103, 115], house mouse (Mus musculus) [80, 81, 83, 85, 118, 120, 124], brown rat (Rattus norvegicus) [82, 85, 103, 108, 117, 118, 120, 124], black rat (Rattus rattus) [83, 85, 86, 92, 103, 118, 120, 124], South African pouched mouse (Saccostomys campestris) [88]; and a range of other free-living mammal species including shrews (Crocidura spp.
Category: