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:…consistent with such a mechanism is supplied by the SSA studies performed in subcortical regions where the responses of adapting units are phasic, being typically restricted to the first 50 ms of the tone or less (Anderson et al., 2009; Malmierca et al., 2009; Pérez-González et al., 2005).
Category: