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:Consistent with this suggestion, administration of agonists at this allosteric glycine binding site results in a significant symptomatic improvement in schizophrenic patients (Javitt et al., 1994; Goff et al., 1995; Heresco-Levy et al., 1996, 1999, 2002; Tsai et al., 1998).
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