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:…report a lack of significant differences between organically and conventionally grown food in terms of safety and nutritional value, suggesting that crops and livestock products produced in both farming systems are comparable with regard to their nutrient content (Smith-Spangler et al. 2012).
Category: