Yunjun ZhangI1,2 and Xiaohua ZhouI1,2,3,4
1 Department of Biostatistics, School of Public Health, Peking University, Beijing, China,
2 Center for Statistical Science, Peking University, Beijing, China,
3 Beijing International Center for Mathematical Research, Peking University, Beijing, China,
4 School of Mathematical Sciences, Peking University, Beijing, China
Correspondence:
Yunjun Zhang School of Public Health, Peking University, Beijing, China.
Email: yunjun.zhang@pku.edu.cn