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:We conducted pairedchoice food trials (Benz et al., 1992; Nunnally, 1978) on individual gorillas and chimpanzees just before mealtimes using foods from the typical diets and several novel foods that varied in nutrient content (Table II).
Category: