- Correspondence to Dr Janet E Rosenbaum, Department of Epidemiology and Biostatistics, School of Public Health, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA;
- Received March 3, 2016
- Revised April 1, 2016
- Accepted April 16, 2016
- First published May 4, 2016.
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.