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:When selecting predictor variables for analysis, we focused on those presumably increasing vulnerability to mange infections or those already mentioned by other authors (Kauhala and Holmala 2006; Collins et al. 2010; Oleaga et al. 2011; Almberg et al. 2012) (Table 2).
Category: