Kathleen M. Carroll, Ph.D.
Opinions expressed in this volume are those of the authors and do not necessarily reflect the opinions or official policy of NIDA or any other part of the U.S. Department of Health and Human Services.
The U.S. Government does not endorse or favor any specific commercial product or company. Trade, proprietary, or company names appearing in this publication are used only because they are considered essential in the context of the models reported herein.
Public Domain Notice
All material appearing in this report is in the public domain and may be reproduced without permission from the National Institute on Drug Abuse or the authors. Citation of the source is appreciated.
National Institute on Drug Abuse
NIH Publication Number 00-4151
Printed July 2000