1. Faculty of Nursing, Health Science Center, Xi’an Jiaotong University, P.R. China
2. College of Nursing and Health Sciences, Flinders University, Australia
3. Xiang Ya Nursing School, Central South University, P.R. China
4. Department of Epidemiology & Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, P.R. China