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:3) revealed that the first two ON1 viruses detected in 2011–2012 (MAD8851/11 and MAD8921/12), clustered together with strains from Canada [Eshaghi et al., 2012], USA [Schobel et al.
Category: