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:With neurodisruption techniques, it is now established that both SEF (Stuphorn and Schall, 2006) and IFG (Chambers et al., 2006, 2007) are critical for inhibitory control.
Category: