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:The processes of tessera formation and their relationship to crustal plateaus have been explored in an extensive body of work [e.g., Head and Crumpler, 1987; Herrick and Phillips, 1990; Bindschadler and Head, 1991; Bindschadler et al., 1992a, 1992b; Bindschadler, 1995; Grimm, 1994; Brown and Grimm, 1997; Hansen and Willis, 1996, 1998; Ivanov and Head, 1996; Pritchard et al., 1997; Gilmore et al., 1997, 1998; Head and Basilevsky, 1998; Phillips and Hansen, 1994, 1998; Hansen et al., 1997, 1999, 2000; Ghent and Hansen, 1999; Banks and Hansen, 2000].
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