- Correspondence to: Pamela M Ling MD MPH, Box 1390, 530 Parnassus Avenue, Suite 366, University of California San Francisco, San Francisco, CA 94143-1390, USA;
- Received January 21, 2005
- Accepted May 19, 2005
- First published September 23, 2005.
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.