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:These results are consistent with preclinical studies
 showing binding to both D3 and D2 receptors in vivo (Gyerty√°n et al. 2011) and preferential binding to D3 receptors in vitro (Kiss et al. 2010) as well as PET studies in nonhuman primates (Seneca et al. 2011; Toth et al. 2013) and humans (Keator‚Ä¶
Category: