1. National Institute on Drug Abuse, Intramural Research Program, Clinical Pharmacology and Therapeutics Research Branch, Baltimore, MD, USA
2. Department of Psychology, Hartwick College, Oneonta, NY, USA
3. National Institute on Drug Abuse, Center for Clinical Trials Network, Bethesda, MD, USA
4. National Institute on Drug Abuse, Intramural Research Program, Biomedical Informatics Section, Baltimore, MD, USA