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:…ADHIB expression as untreated basal conditions in all ADHIB haplotypes following exposure to 1.5 mg ml 1 concentration (36 mM) and is consistent with low concentration EtOH effects observed in other cell types (Chen et al., 1993; D’Souza et al., 1994; De Vito et al., 2000; Nakatani et al., 2002).
Category: