Dyfyniad APA

World Health Organization. (2011). International travel and health. World Health Organization.

Dyfyniad Arddull Chicago

World Health Organization. International Travel and Health. Geneva, Switzerland: World Health Organization, 2011.

Dyfyniad MLA

World Health Organization. International Travel and Health. World Health Organization, 2011.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.