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:In this regard, it is worth noting that the number of studies that have reported at least some mixed strain infections in a wide variety of hosts, including cats, has increased greatly since more sensitive genotyping techniques have been applied (AlKappany et al., 2010; Aspinall et al., 2003; Boughattas et al., 2010; Dubey et al., 2007b, 2009b, 2006a,b,c, 2005; ElbezRubinstein et al., 2009; Lindstrom et al., 2008; Mercier et al., 2010; Parameswaran et al., 2010; Ragozo et al., 2010; Sundar et al., 2008; Yai et al., 2009).
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