1. Center for Applied Mathematics Tianjin University Tianjin China
2. Division of Biomedical Statistics and Informatics Mayo Clinic Rochester Minnesota USA
3. Department of Biostatistics College of Global Public Health, New York University New York New York USA
4. Division of Biostatistics Department of Population Health, New York University School of Medicine New York New York USA
5. Division of Biostatistics Washington University in St. Louis St. Louis Missouri USA