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Cheng HG, Anthony JC, Huang Y, Lee S, Liu Z, He Y.Cheng HG, et al.Drug Alcohol Depend. 2011 Oct 1;118(1):31-9. doi: 10.1016/j.drugalcdep.2011.02.013. Epub 2011 Apr 6.Drug Alcohol Depend. 2011.PMID: 21474254Free PMC article.