- D T Felson, Clinical Epidemiology Research and Training Unit, 715 Albany Street A203, Boston, MA 02118, USA;
- Accepted May 7, 2007
- First published May 14, 2007.
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.