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:This finding was in complete agreement with previous reports in which E2 was found to be more antigenic than E1 in infected patients (Edwards et al., 2012; Neumann-Haefelin & Thimme, 2013; Prince et al., 1999; Shimizu et al., 1994; Wahid & Dubuisson, 2013; Wang et al., 2011).
Category: