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:The type species, Aedes aegypti densonucleosisvirus (AaeDNV) genome encodes two overlapping ORFs the nonstructural proteins, NS1 and NS2 (Afanasiev et al., 1991).
Category: