- Correspondence to Dr Jun Lv, Department of Epidemiology and Biostatistics, Peking University Health Science Center, 38 Xueyuan Road, Beijing 100191, China; ; or Prof Liming Li, Department of Epidemiology and Biostatistics, Peking University Health Science Center 38 Xueyuan Road, Beijing 100191, China; email@example.com.
- Received 13 August 2016
- Revised 9 December 2016
- Accepted 16 December 2016
- Published in print 1 May 2017.
- Published online 26 April 2017.
- Published first 11 January 2017.
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