National Institute on Drug Abuse, fact sheets on specific drugs and drug issues and research reports on key drug issues

National Institutes of Health, Research Portfolio Online Reporting Tools (RePORT) grants database

National Survey on Drug Use and Health from the Substance Abuse and Mental Health Services Administration, part of the U.S. Department of Health and Human Services

Relationship between Nonmedical Prescription-Opioid Use and Heroin Use,” Wilson Compton in The New England Journal of Medicine

Nonmedical Prescription Opioid Use and Use Disorders Among Adults Aged 18 Through 64 Years in the United States, 2003-2013,” Wilson Compton in the Journal of the American Medical Association