1. School of Statistics Renmin University of China Beijing P. R. China
2. Division of Clinical and Translational Sciences Department of Internal Medicine University of Texas Health Science Center at Houston Houston TX USA
3. School of Mathematics and Statistics Wuhan University Wuhan P. R. China
4. Department of Statistics University of Missouri Columbia MO USA
5. Biostatistics Department St. Jude Children's Research Hospital Memphis TN USA
6. Epidemiology and Cancer Control St. Jude Children's Research Hospital Memphis TN USA