8Amare A, Yami A. Case-fatality of adult tetanus at Jimma University Teaching Hospital, Southwest Ethiopia [J]. Afr Health Sci, 2011,11(1): 36-40.
9Centers for Disease Control and Prevention (CDC). Epidemiology and prevention of vaccine - preventable diseases [ M . 10th ed. Washington, DC : Public Health Foundation,2008:273 - 282.