- Correspondence to Dr Alex R Cook, National University Singapore Saw Swee Hock School of Public Health, Singapore 117549;
- Received June 27, 2018
- Revised April 1, 2019
- Accepted April 10, 2019
- First published May 9, 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.