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:8) with poor oral bioavailability thus necessitating administration of relatively high doses (300–450 mg/kg body weight in preclinical models) for optimal therapeutic benefits (Aneja et al., 2007; Ke et al., 2000; Ye et al., 1998).
Category: