- Correspondence to Dr M Halliday, University of Alabama at Birmingham, Birmingham, AL, USA;
- Received July 19, 2013
- Accepted July 23, 2013
- First published September 12, 2013.
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.