1. Johnston L, O’Malley PM, Bachmann JG. National survey results on drug use: Monitoring the Future, 1975–92. Rockville, MD: National Institute on Drug Abuse. U.S. Dept. of Health and Human Services Pub. No. NIH 93-3597,93-3598, 1993.
2. Hibell B, Andersson B, Bjarnasson T, et al. The 1995 ESPAD Report. Strasbourg, France: Council of Europe. Co-operation Group to Combat Drug Abuse and Illicit Trafficing in Drug (Pompidou Group). The Swedish Council for Information on Alcohol and Other Drugs, Canada, 1995.
3. American Academy of Pediatrics, Committee on Substance Abuse. The role of schools in combatting substance abuse. Pediatrics 1995;95:784–5.
4. Stages in adolescent involvement with drug use;Kandel;Science,1975
5. Patterns of drug use from adolescene to young adulthood;Yamaguchi;Am J Public Health,1984