- Wallace Pickworth, PhD, NIDA, Intramural Research Program, Addiction Research Center, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA
- Received June 29, 2000
- Revised October 23, 2000
- Accepted February 6, 2001
- First published June 1, 2001.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.