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:Our suggestion that the Andropogoneae of the Panicoid subfamily is monophyletic diVers from the results from the tb1 gene (Lukens and Doebley 2001), but is in agreement with reports based on other genes (Clark et al.
Category: