1. The University of Mississippi Potency Monitoring Project, 2002. http://www.dea.gov/concern/18862/marijuan.htm.
2. On the preparation of Indian hemp and gunjah;O'Shaughnessy;Trans Med Phys Soc Bombay,1842
3. National survey results on drug use from the Monitoring the Future Study, 1975–1995;Johnston,1995
4. Monitoring the Future National Survey results on drug use, 1975–2003. Volume I: Secondary school students (National Institutes of Health Publication No. 04–5507);Johnston,2004
5. Results from the 2002 National Survey on Drug Use and Health: national findings (Department of Health and Human Services Publication No. SMA 03–3836);Substance Abuse and Mental Health Services Administration,2003