1. Department of Oromaxillofacial-Head and Neck Surgery, Department of Oral and Maxillofacial Surgery, School of StomatologyChina Medical University
No. 117, Nanjing North Street
110002 Shenyang Liaoning China
2. The Library of Liaoning University of Traditional Chinese Medicine
No. 79, Chongshan Road East
110847 Shenyang Liaoning China
3. Department of Biostatistics and Epidemiology, School of Public HealthChina Medical University
No. 77 Puhe Road
110122 Shenyang Liaoning China