World Health Organization. (2000). International travel and health: Vaccination requirements and health advice. World Health Organization.
Chicago-viite (17. p.)World Health Organization. International Travel and Health: Vaccination Requirements and Health Advice. Geneva: World Health Organization, 2000.
MLA-viite (8. p.)World Health Organization. International Travel and Health: Vaccination Requirements and Health Advice. World Health Organization, 2000.
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