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:Hissink et al. (1997) also reported that elimination of 1,4-DCB via the lungs was less than 1% in rats orally dosed p-DCB (10–250 mg/kg body weight).
Category: