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:Under 1 mmol m 2 s 1 red light, prr5-1 and ZTL-ox displayed longer hypocotyls, whereas ztl mutants and 35S-PRR5 showed shorter hypocotyls (Figure 8A) (Sato et al., 2002; Yamamoto et al., 2003; Somers et al., 2004).
Category: