World Health Organization. (2000). International travel and health: Vaccination requirements and health advice. World Health Organization.
Chicago-Zitierstil (17. Ausg.)World Health Organization. International Travel and Health: Vaccination Requirements and Health Advice. Geneva: World Health Organization, 2000.
MLA-Zitierstil (8. Ausg.)World Health Organization. International Travel and Health: Vaccination Requirements and Health Advice. World Health Organization, 2000.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.