World Health organization. (2012). International travel and health. World Health Organization.
Chicago (17e ed.) BronvermeldingWorld Health organization. International Travel and Health. Geneva, Switzerland: World Health Organization, 2012.
MLA (8e ed.) BronvermeldingWorld Health organization. International Travel and Health. World Health Organization, 2012.
Let op: Deze citaties zijn niet altijd 100% accuraat.