World Health Organization. (2011). World health statistics 2011. World Health Organization.
Chicago-referens (17:e uppl.)World Health Organization. World Health Statistics 2011. Geneva, Switzerland: World Health Organization, 2011.
MLA-referens (8:e uppl.)World Health Organization. World Health Statistics 2011. World Health Organization, 2011.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.