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:…channels and chronic drug-induced disruption of hERG protein trafficking into the cell surface membrane (Ficker et al. 2004; Cordes et al. 2005; Kuryshev et al. 2005; Wible et al. 2005; Rajamani et al. 2006; Thomas et al. 2006; Guo et al. 2007; Takemasa et al. 2007; Wang et al. 2007; Van der…
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