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:…neurons at their long (>1,000 m) dendrites (Campbell et al., 2005) or at their axons in this study, interaction of GnIH-ir fibers with GnRH-I neurons is consistent with results in birds (Bentley et al., 2003; Ubuka et al., 2008a), rodents (Kriegsfeld et al., 2006), and sheep (Smith et al., 2008).
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