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:This con®rms our and other's recent ®ndings in the rat (Porcella et al., 1998) and human (Straiker et al., 1999; Porcella et al. 2000) ciliary bodies of signi®cantly detectable levels of CB1 transcripts and proteins.
Category: