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:These results corroborate the hypothesis that there is a possible link between HHC and schizophrenia (Regland et al., 1995; Regland, 2005; Susser et al., 1998; Levine et al., 2002; Applebaum et al., 2004; Brown and Susser, 2005; Muntjewerff et al., 2005, 2006; Neeman et al., 2005; Lee et al., 2006; Adler Nevo et al., 2006; Haidemenos et al., 2007; Akanji et al., 2007).
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