Mangram AJ, Horan TC, Pearson ML, et al. : Guideline for prevention of surgical site infection, 1999. Infection control and hospital epidemiology 1999 ; 20 : 250~278 ; quiz 79-80.
WHO guidelines for safe surgery : safe surgery saves lives. http://www.who.int/patientsafety/safesurgery/tools_resources/9789241598552/en/