World Health Organization. (2011). World health statistics 2011. World Health Organization.
Cita Chicago Style (17a ed.)World Health Organization. World Health Statistics 2011. Geneva, Switzerland: World Health Organization, 2011.
Cita MLA (8a ed.)World Health Organization. World Health Statistics 2011. World Health Organization, 2011.
Precaución: Estas citas no son 100% exactas.