- A J Henderson, ALSPAC, University of Bristol, Oakfield House, Oakfield Grove, Clifton, Bristol BS8 2BN, UK;
- Accepted January 6, 2009
- First published January 15, 2009.
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.