REFERENCES
  1. Tetanus (PDF). CDC Pink Book. Retrieved 2007-01-26
  2. Atkinson, William (May 2012). Tetanus Epidemiology and Prevention of Vaccine-Preventable Diseases (12 ed). Public Health Foundation. Pp. 291-300. ISBN 9780983263135. Retrieved 12 Feb 2015.
  3. Tetanus Symptoms and Complications. cdc.gov. January 9, 2013. Retrieved 12 February 2015.
  4. http://textbookofbacteriology.net/themicrobialworld/Tetanus.html.
  5. Tetanus–Puerto Rico, 2002. MMWR Morb Mortal Wkly Rep . 2002 Jul 19. 51(28):613-5.