- Correspondence to Maarten Boers, Department of Epidemiology and Biostatistics, VU University Medical Center, PK 6Z 165, PO Box 7057, 1007 MB Amsterdam, The Netherlands;
- Accepted June 27, 2009
- First published December 9, 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.