- Correspondence to Professor Pingmin Wei, Teaching and Research Office of Epidemiology and Health Statistics, School of Public Health, Southeast University, 87 Dingjiaqiao Road (W), Nanjing 210009, China; and Professor Ping Zhong, Department of AIDS and STD, Shanghai Municipal Center for Disease Control and Prevention, Shanghai Municipal Institutes for Preventive Medicine, 1380 Zhongshan Road (W), Shanghai 200336, China;
- Received December 26, 2016
- Revised May 10, 2017
- Accepted June 10, 2017
- First published August 7, 2017.
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