- Correspondence to Dr Xiang Qian Lao, Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, School of Public Health, Prince of Wales Hospital, Sha Tin, N.T, Hong Kong SAR, China;
- Received May 14, 2017
- Revised September 13, 2017
- Accepted October 11, 2017
- First published November 13, 2017.
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