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:…themselves, as has been proposed previously [e.g., Bindschadler et al., 1992a, 1992b; Bindschadler, 1995; Hansen et al., 1997, 1999, 2000; Gilmore et al., 1998; Ghent and Hansen, 1999], then the structures preserved in crustal plateaus can provide important insights into Venus’ geological history.
Category: