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:…DCN following acoustic trauma is expected from the previously reported trauma-induced loss of glycinergic receptors and associated molecules in DCN (Asako et al. 2005; Wang et al. 2009; Whiting et al. 2009) and from the weakening of glycinergic post-synaptic potentials in VCN (Xie and Manis 2013).
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