APA (7th ed.) Zitazioa
World Health Organization & ebrary, Inc. (2007). International travel and health: Situation as on 1 January 2007. World Health Organization.
Chicago Style (17th ed.) Zitazioa
World Health Organization eta Inc ebrary. International Travel and Health: Situation as on 1 January 2007. Geneva: World Health Organization, 2007.
MLA (9th ed.) Zitazioa
World Health Organization eta Inc ebrary. International Travel and Health: Situation as on 1 January 2007. World Health Organization, 2007.
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