- Correspondence to: Dr S S Weir Campus Box, #8120 Carolina Population Center, University of North Carolina, Chapel Hill, NC 27516-3997, USA;
- Accepted August 20, 2004
- First published November 30, 2004.
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.