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:…tRNA selection on the ribosome during protein synthesis (Blanchard et al., 2004) (reviewed in Johansson et al., 2008; Rodnina et al., 2005), acetylcholine receptor desensitization (Dilger and Brett, 1990; Matsubara et al., 1992), and subunit rotation of F0F1-ATP synthase (Diez et al., 2004).
Category: