- Correspondence to Dr Yiqiang Zhan, Karolinska Institutet Department of Medical Epidemiology and Biostatistics, Stockholm 17177, Sweden;
- Received July 1, 2019
- Revised October 18, 2019
- Accepted October 25, 2019
- First published November 14, 2019.
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.