United Nations Environmental Program. (1987). State of the Environment: The state of the world environment. United Nations Environmental Program.
Chicago-Zitierstil (17. Ausg.)United Nations Environmental Program. State of the Environment: The State of the World Environment. Nairobi, Kenya: United Nations Environmental Program, 1987.
MLA-Zitierstil (9. Ausg.)United Nations Environmental Program. State of the Environment: The State of the World Environment. United Nations Environmental Program, 1987.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.