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:Previous studies have shown that consumers are able to discern different applications of a category of emerging technologies (namely various products of nanotechnology) and have different attitudes about risks, benefits, and labeling for those applications (e.g., Brown and Kuzma 2013; Siegrist et al. 2007).
Category: