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:IL-10 is also considered to be an anti-inflammatory cytokine, but in contrast to most anti-inflammatory cytokines IL-10 concentrations increases during endurance exercise in thermoneutral conditions (Nieman et al. 2012; Peake et al. 2005, 2008; Svendsen et al. 2014) and increases further when exercise is conducted in a hot laboratory environment (Peake et al.
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