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 have been reported in other species such as Atlantic salmon (Salmo salar) (Bell et al. 1993; Ruyter et al. 2006), brown trout (Salmo trutta) (Tocher et al.
Category: