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:3B as well as in prior work (Boly et al., 2012; Doucet et al., 2011; Lee et al., 2012;Marrelec et al., 2008), RSNs are hierarchically organized.
Category: